Fluorescent protein sensors for detection of analytes

ABSTRACT

Fluorescent indicators including a binding protein moiety, a donor fluorescent protein moiety, and an acceptor fluorescent protein moiety are described. The binding protein moiety has an analyte-binding region which binds an analyte and causes the indicator to change conformation upon exposure to the analyte. The donor moiety and the acceptor moiety change position relative to each other when the analyte binds to the analyte-binding region. The donor moiety and the acceptor moiety exhibit fluorescence resonance energy transfer when the donor moiety is excited and the distance between the donor moiety and the acceptor moiety is small. The indicators can be used to measure analyte concentrations in samples, such as calcium ion concentrations in cells.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

This invention was made with Government support under Grant No. NS27177, awarded by the National Institutes of Health. The Government has certain rights in this invention.

BACKGROUND OF THE INVENTION

The invention relates to fluorescent protein sensors for detecting and quantifying analytes.

Measurement of an analyte concentration in vitro or in vivo by non-invasive techniques can help elucidate the physiological function of the analyte. This can also aid in identifying changes that occur in a cell or organism in response to physiological stimuli. For example, cyclic AMP can be detected by fluorescence resonance energy transfer between a separately labeled proteins that associate with each other but are not covalently attached to each other. See, U.S. Pat. No. 5,439,797.

For example, many effects of Ca²⁺ in cells are mediated by Ca²⁺ binding to calmodulin (CaM), which causes CaM to bind and activate target proteins or peptide sequences. Based on the NMR solution structure of CaM bound to the 26-residue M13 Ca²⁺ -binding peptide of myosin light-chain kinase, Porumb et al. fused the C-terminus of CaM via a Gly-Gly spacer to the M13. Ca²⁺ binding switches the resulting hybrid protein (CaM-M13) from a dumbbell-like extended form to a compact globular form similar to the CaM-M13 intermolecular complex. See, Porumb, T., et al., Prot. Engineering 7:109-115 (1994).

Fluorescent Ca²⁺ indicators such as fura-2, indo-1, fluo-3, and Calcium-Green have been the mainstay of intracellular Ca²⁺ measurement and imaging. See, for example, U.S. Pat. No. 4,603,209 and U.S. Pat. No. 5,049,673. These relatively low molecular weight indicators can suffer from many technical problems relating to ester loading, leakage of the dyes from the cell, compartmentation in organelles, and perturbation of the indicators by cellular constituents. Although the Ca²⁺ -indicating photoprotein aequorin is targetable, the photoresponse to Ca²⁺ is low since it is chemiluminescent. Moreover, aequorins need to incorporate exogenous coelenterazine.

SUMMARY OF THE INVENTION

This invention provides fluorescent indicators and methods for using them to determine the concentration of an analyte both in vitro and in vivo. In one aspect, the fluorescent indicator includes a binding protein moiety, a donor fluorescent protein moiety, and an acceptor fluorescent protein moiety. The binding protein moiety has an analyte-binding region which binds an analyte and causes the indicator to change conformation upon exposure to the analyte. The donor fluorescent protein moiety is covalently coupled to the binding protein moiety. The acceptor fluorescent protein moiety is covalently coupled to the binding protein moiety. In the fluorescent indicator, the donor moiety and the acceptor moiety change position relative to each other when the analyte binds to the analyte-binding region, altering fluorescence resonance energy transfer between the donor moiety and the acceptor moiety when the donor moiety is excited.

The donor fluorescent protein moiety and the acceptor fluorescent protein moiety can be Aequorea-related fluorescent protein moieties. Preferably, the donor fluorescent protein moiety is P4-3, EBFP, or W1B, and the acceptor fluorescent protein moiety is S65T, EGFP, or 10c.

In preferred embodiments, the indicator further includes the target peptide moiety and a linker moiety that covalently couples the binding protein and the target peptide moiety. The binding protein moiety further includes a peptide-binding region for binding the target peptide moiety. The binding protein moiety can be covalently coupled to the donor fluorescent protein moiety and the target peptide moiety can be covalently coupled to the acceptor fluorescent protein moiety.

The indicator can be a single polypeptide. In preferred embodiments, one of the donor fluorescent protein moiety or the acceptor fluorescent protein moiety is covalently coupled to the carboxy terminus of the single polypeptide and the other of the donor fluorescent protein moiety or the acceptor fluorescent protein moiety is covalently coupled to the amino terminus of the single polypeptide.

The indicator can include a localization sequence. The localization sequence can be a nuclear localization sequence, an endoplasmic reticulum localization sequence, a peroxisome localization sequence, a mitochondrial import sequence, a mitochondrial localization sequence, or a localized protein.

In preferred embodiments, the linker moiety is a peptide moiety. The linker moiety can include between about 1 amino acid residue and about 20 amino acid residues. The linker moiety can be --Gly-Gly--.

Preferably, the binding protein moiety is calmodulin, a calmodulin-related protein moiety, cGMP-dependent protein kinase, a steroid hormone receptor, a ligand binding domain of a steroid hormone receptor, protein kinase C, inositol-1,4,5-triphosphate receptor, or recoverin. A calmodulin-related protein moiety is derived from calmodulin that has been modified to have a different binding affinity for calcium or a target peptide moiety.

Most preferably, the binding protein moiety is calmodulin or a calmodulin-related protein moiety. In these embodiments, the target peptide moiety can be a subsequence of a calmodulin-binding domain of M13, smMLCKp, CaMKII, Caldesmon, Calspermin, Calcineurin, PhK5, PhK13, C28W, 59-kDa PDE, 60-kDa PDE, NO-30, AC-28, Bordetella pertussis AC, Neuromodulin, Spectrin, MARCKS, F52, β-Adducin, HSP90a, HIV-1 gp160, BBMHBI, Dilute MHC, Mastoparan, Melittin, Glucagon, Secretin, VIP, GIP, or Model Peptide CBP2. Preferably, the target peptide moiety is M13.

In another aspect, the invention features a fluorescent indicator including a target peptide moiety, a binding protein moiety, a linker moiety, a donor fluorescent protein moiety covalently coupled to the binding protein moiety, and an acceptor fluorescent protein moiety covalently coupled to the binding protein moiety. The binding protein moiety has an analyte-binding region which binds an analyte and causes the indicator to change conformation upon exposure to the analyte. The linker moiety covalently couples the binding protein and the target peptide moiety and is a peptide moiety. The binding protein moiety has a peptide-binding region for binding the target peptide moiety. The indicator is a single polypeptide.

In another aspect, the invention features a method for determining the concentration of an analyte in a sample. The method includes the steps of contacting the sample with a fluorescent indicator having a donor fluorescent protein moiety, binding protein moiety, and acceptor protein moiety, exciting the donor moiety, and determining the degree of fluorescence resonance energy transfer in the sample corresponding to the concentration of the analyte in the sample.

In preferred embodiments, the step of determining the degree of fluorescence resonance energy transfer in the sample includes measuring light emitted by the acceptor fluorescent protein moiety. In other preferred embodiments, determining the degree of fluorescence resonance energy transfer in the sample includes measuring light emitted from the donor fluorescent protein moiety, measuring light emitted from the acceptor fluorescent protein moiety, and calculating a ratio of the light emitted from the donor fluorescent protein moiety and the light emitted from the acceptor fluorescent protein moiety. In yet other preferred embodiments, determining the degree of fluorescence resonance energy transfer in the sample includes measuring the excited state lifetime of the donor moiety.

The method can further include the steps of determining the concentration of the analyte at a first time after contacting the sample with the fluorescence indicator, determining the concentration of the analyte at a second time after contacting the sample with the fluorescence indicator, and calculating the difference in the concentration of the analyte at the first time and the second time, whereby the difference in the concentration of the analyte in the sample reflects a change in concentration of the analyte present in the sample.

In other embodiments, the method can further include the step of contacting the sample with a compound between the first time and the second time, whereby a difference in the concentration of the analyte in the sample between the first time and the second time indicates that the compound alters the presence of the analyte.

In preferred embodiments, the sample includes an intact cell and the contacting step includes incorporating the fluorescent indicator into the cell. The step of incorporating the fluorescent indicator into the cell can include transfecting the cell with an expression vector comprising expression control sequences operably linked to a nucleic acid sequence coding for the expression of the fluorescent indicator. The preferred analyte is calcium.

In yet another aspect, the invention features an isolated nucleic acid sequence which encodes the fluorescent indicator. In preferred embodiments, an expression vector or a transgenic non-human animal includes the nucleic acid sequence.

In another aspect, the invention features an expression vector including expression control sequences operatively linked to a nucleic acid sequence coding for the expression of the fluorescent indicator. The expression vector can be adapted for function in a prokaryotic cell or a eukaryotic cell.

In another aspect of the invention, a host cell transfected with an expression vector can include an expression control sequence operatively linked to a sequence coding for the expression of the fluorescent indicator. The cell can be a prokaryote, such as E. coli, or a eukaryotic cell, such as a yeast cell or mammalian cell.

In another aspect, the invention features a transgenic non-human animal having a phenotype characterized by expression of the nucleic acid sequence coding for the expression of the fluorescent indicator. The phenotype is conferred by a transgene contained in the somatic and germ cells of the animal. The animal can be a mouse.

In another aspect, the invention features a method for producing a transgenic non-human animal having a phenotype characterized by expression of the nucleic acid sequence coding for the expression of the fluorescent indicator. The method includes the steps of: (a) introducing a transgene into a zygote of an animal, the transgene comprising a DNA construct encoding the fluorescent indicator; (b) transplanting the zygote into a pseudopregnant animal; (c) allowing the zygote to develop to term; and (d) identifying at least one transgenic offspring containing the transgene. The step of introducing of the transgene into the embryo can be by introducing an embryonic stem cell containing the transgene into the embryo, or infecting the embryo with a retrovirus containing the transgene.

"Peptide" refers to a polymer in which the monomers are amino acid residues which are joined together through amide bonds, alternatively referred to as a polypeptide. A "single polypeptide" is a continuous peptide that constitutes the protein. When the amino acids are alpha-amino acids, either the L-optical isomer or the D-optical isomer can be used, the L-isomers being preferred. Additionally, unnatural amino acids such as beta-alanine, phenylglycine, and homoarginine are meant to be included. Commonly encountered amino acids which are not gene-encoded can also be used in the present invention, although preferred amino acids are those that are encodable. For a general review, see, for example, Spatola, A. F., in Chemistry and Biochemistry of Amino Acids, Peptides and Proteins, B. Weinstein, ed., Marcel Dekker, New York, p. 267 (1983).

"Fluorescent protein" refers to any protein capable of emitting light when excited with appropriate electromagnetic radiation. Fluorescent proteins include proteins having amino acid sequences that are either natural or engineered, such as the fluorescent proteins derived from Aequorea-related fluorescent proteins.

In FRET, the "donor fluorescent protein moiety" and the "acceptor fluorescent protein moiety" are selected so that the donor and acceptor moieties exhibit fluorescence resonance energy transfer when the donor moiety is excited. One factor to be considered in choosing the donor/acceptor fluorescent protein moiety pair is the efficiency of FRET between the two moieties. Preferably, the efficiency of FRET between the donor and acceptor moieties is at least 10%, more preferably at least 50%, and most preferably at least 80%. The efficiency of FRET can be tested empirically using the methods described herein and known in the art, particularly, using the conditions set forth in the Examples.

"Covalently coupled" refers to a covalent bond or other covalent linkage between two moieties. The covalent linkage can include a diradical moiety linking to two moieties.

"Binding protein" refers to a protein capable of binding an analyte. Preferred binding proteins change conformation upon binding the analyte. "Target peptide" refers to a peptide that can bind to the binding protein. The target peptide can be a subsequence of a peptide that binds to the binding protein.

"Analyte" refers to a molecule or ion in solution that binds to the binding protein, causing it to change conformation. Preferably, the analyte binds reversibly to the binding protein.

"Moiety" refers to a radical of a molecule that is attached to another radical of the indicator. Thus, a "fluorescent protein moiety" is the radical of a fluorescent protein coupled to a binding protein moiety or a linker moiety, a "binding protein moiety" is a radical of a binding protein coupled to a fluorescent protein moiety, a "target peptide moiety" is a radical of a target peptide of the binding protein, and a "linker moiety" refers to the radical of a molecular linker that is ultimately coupled to both the donor and acceptor fluorescent protein moieties.

"Operatively linked" refers to a juxtaposition wherein the components so described are in a relationship permitting them to function in their intended manner. A control sequence operatively linked to a coding sequence is ligated such that expression of the coding sequence is achieved under conditions compatible with the control sequences. "Control sequence" refers to polynucleotide sequences which are necessary to effect the expression of coding and non-coding sequences to which they are ligated. Control sequences generally include promoter, ribosomal binding site, and transcription termination sequence. The term "control sequences" is intended to include, at a minimum, components whose presence can influence expression, and can also include additional components whose presence is advantageous, for example, leader sequences and fusion partner sequences.

"Polynucleotide" refers to a polymeric form of nucleotides of at least 10 bases in length. The nucleotides can be ribonucleotides, deoxynucleotides, or modified forms of either type of nucleotide. The term includes single and double stranded forms of DNA.

The invention can have one or more of the following advantages. Ligand-induced conformational changes can be monitored by FRET if, for example, the amino and carboxy termini of the binding protein are fused to a donor and acceptor GFP. This approach has several advantages over the usual covalent labeling with fluorescent probes. The fluorescent indicator can be generated in situ by gene transfer into the cells or organisms. This approach avoids the need to express and purify large quantities of soluble recombinant protein, purify and label it in vitro, microinject it back into cells. The fluorescent indicator can be targeted to cellular structures. The sites of fusion between the moieties of the fluorescent indicator are exactly defined, giving a molecularly homogenous product without relying on elaborate protein chemistry. In addition, the chromophore of GFP is fixed in the protein. See, Ormo, M., et al., Science 273:1392-1395 (1996). If the GFP donor and acceptor are fused to a host protein rigidly, minor changes in the relative orientation of the ends of the latter would alter FRET. In contrast, most conventional fluorescent labels are attached by flexible linkers that at least partially decouple the fluorophore orientation from that of the protein to which it is attached, limiting the sensitivity of the FRET measurement.

Other features or advantages of the present invention will be apparent from the following detailed description of the invention, and also from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram depicting a fluorescent indicator that measures the concentration of an analyte by fluorescence resonance energy transfer.

FIG. 2a is a schematic diagram depicting the structure of chimera proteins containing P4-3, CaM-M13, and S65T, where HIS is the amino-terminal tag peptide containing the polyhistidine sequence and XCaM is Xenopus calmodulin.

FIG. 2b is a diagram depicting the amino acid and nucleotide sequences of the boundaries between P4-3 and CaM (SEQ ID NOS:57 and 58) and between M13 and S65T in cameleon-1 (SEQ ID NOS:59 and 60).

FIG. 3 is a graph depicting the emission spectra of cameleon-1 before and after addition of 2 mM CaCl₂ to give 1 mM free Ca²⁺.

FIG. 4a is a graph depicting the change in emission spectrum of cameleon-1 on titration with Ca²⁺ when excited at 380 nm.

FIG. 4b is a graph depicting Ca²⁺ titration curves of cameleon-1 (open circles) and cameleon-1/E104Q (solid circles).

FIG. 5 is a schematic diagram depicting the structures of cameleon-2 and cameleon-3, and their derivatives, cameleon-2nu and cameleon-3er, where Kz is Kozak's consensus sequence (SEQ ID NO:61).

FIG. 6a is a digital fluorescence image depicting fluorescence of cameleon-2 localized to the cytosol of HeLa cells, where the bar is 10 μm.

FIG. 6b is a graph depicting temporal changes in the emission ratio of cameleon-2 for each of the HeLa cells shown in FIG. 6a.

FIG. 6c is a digital fluorescence image depicting fluorescence of cameleon-2nu localized to the nuclei of HeLa cells, where the bar is 10 μm.

FIG. 6d is a graph depicting temporal changes in the emission ratio of cameleon-2nu in the two nuclei shown in FIG. 6c.

FIG. 6e is a digital fluorescence image depicting fluorescence of cameleon-3er in transfected HeLa cells, where the bar is 10 μm.

FIG. 6f is a graph depicting the time-course of emission ratio of cameleon-3er (average of four cells).

FIG. 7 depicts the nucleotide sequence (SEQ ID NO:1) and amino acid sequence (SEQ ID NO:2) of cameleon-2.

FIG. 8 depicts the nucleotide sequence (SEQ ID NO:3) and amino acid sequence (SEQ ID NO:4) of cameleon-2nu.

FIG. 9 depicts the nucleotide sequence (SEQ ID NO:5) and amino acid sequence (SEQ ID NO:6) of cameleon-3.

FIG. 10 is a list depicting the nucleotide sequence (SEQ ID NO:7) and amino acid sequence of cameleon-3er (SEQ ID NO:8).

DETAILED DESCRIPTION

A fluorescent indicator that utilizes fluorescent resonance energy transfer ("FRET") to measure the concentration of an analyte includes two fluorescent protein moieties having emission and excitation spectra that render one a donor fluorescent protein moiety and the other an acceptor fluorescent protein moiety. The fluorescent protein moieties are chosen such that the excitation spectrum of one of the moieties (the acceptor fluorescent protein moiety) overlaps with the emission spectrum of the excited protein moiety (the donor fluorescent protein moiety). The donor and acceptor fluorescent protein moieties are bound to a binding protein moiety that changes conformation upon binding the analyte. The change in conformation leads to a change in relative position and orientation of the donor and acceptor fluorescent protein moieties, thereby altering the relative amounts of fluorescence from the two fluorescent protein moieties when the donor is excited by irradiation. In particular, binding of the analyte changes the ratio of the amount of light emitted by the donor and acceptor fluorescent protein moieties. The ratio between the two emission wavelengths provides a measure of the concentration of the analyte in the sample, which is based in part on the binding affinity of the binding protein moiety and the analyte.

Referring to FIG. 1, the donor fluorescent protein moiety is covalently linked to a first region (e.g., the amino terminus) of the binding protein moiety, and the acceptor fluorescent protein moiety is covalently linked to a second region (e.g., the carboxy terminus) of the binding protein moiety such that the donor and acceptor moieties move closer together upon binding the analyte. Alternatively, the donor and acceptor moieties can move farther apart upon binding the analyte. In one embodiment, depicted in FIG. 1, the acceptor moiety is covalently bonded to a target peptide moiety that also binds to the binding protein moiety and the target peptide moiety is covalently bonded to the binding protein moiety by a linker moiety. The linker moiety is flexible enough to allow the target peptide moiety to bind to the binding protein moiety. The donor moiety is excited by light of appropriate intensity within the excitation spectrum of the donor moiety (λ_(excitation)). The donor moiety emits the absorbed energy as fluorescent light (λ_(emission) 1). When the acceptor fluorescent protein moiety is positioned to quench the donor moiety in the excited state, the fluorescence energy is transferred to the acceptor moiety which can emit fluorescent light (λ_(emission) 2). FRET can be manifested as a reduction in the intensity of the fluorescent signal from the donor moiety (λ_(emission) 1), reduction in the lifetime of the excited state of the donor moiety, or emission of fluorescent light at the longer wavelengths (lower energies) characteristic of the acceptor moiety (λ_(emission) 2). When the conformation of the binding protein moiety changes upon binding the analyte, the fluorescent protein moieties come closer together (or physically separate), and FRET is increased (or decreased) accordingly.

The efficiency of FRET depends on the separation distance and the orientation of the donor and acceptor fluorescent protein moieties. For example, the Forster equation describes the efficiency of excited state energy transfer, based in part on the fluorescence quantum yield of the donor moiety and the energetic overlap with the acceptor moiety. The Forster equation is:

    E=(F.sub.0 -F)/F.sub.0 =R.sub.0.sup.6 /(R.sup.6 +R.sub.0.sup.6)

where E is the efficiency of FRET, F and F₀ are the fluorescence intensities of the donor moiety in the presence and absence of the acceptor, respectively, and R is the distance between the donor moiety and the acceptor moiety.

The characteristic distance R₀ at which FRET is 50% efficient depends on the quantum yield of the donor moiety (i.e., the shorter-wavelength fluorophore), the extinction coefficient of the acceptor moiety (i.e., the longer-wavelength fluorophore), and the overlap between the emission spectrum of the donor moiety and the excitation spectrum of the acceptor moiety. R₀ is given (in Å) by

    R.sub.0 =9.79×10.sup.3 (K.sup.2 QJn.sup.-4).sup.1/6

where K² is an orientation factor having an average value close to 0.67 for freely mobile donors and acceptors, Q is the quantum yield of the unquenched donor moiety, n is the refractive index of the medium separating the donor moiety and the acceptor moiety, and J is the overlap integral. J can be quantitatively expressed as the degree of spectral overlap between the donor moiety and the acceptor moiety according to the equation:

    J=∫.sup.∞.sub.0 ε.sub.λ F.sub.λ λ.sup.4 dλ/∫.sup.∞.sub.0 F.sub.λ dλ

where ε.sub.λ (M⁻¹ cm⁻¹) is the molar absorptivity of the acceptor and F.sub.λ is the donor moiety fluorescence intensity at wavelength λ. See, for example, Forster, T. Ann.Physik 2:55-75 (1948). Tables of spectral overlap integrals are readily available to those working in the field (for example, Berlman, I. B. Energy transfer parameters of aromatic compounds, Academic Press, New York and London (1973)). FRET is a nondestructive spectroscopic method that can monitor proximity and relative angular orientation of fluorophores in living cells. See, for example, Adams, S. R., et al., Nature 349:694-697 (1991), and Gonzalez, J. & Tsien, R. Y. Biophy.J. 69:1272-1280 (1995).

These factors need to be balanced to optimize the efficiency and detectability of FRET from the fluorescent indicator. The emission spectrum of the donor fluorescent protein moiety should overlap as much as possible with the excitation spectrum of the acceptor fluorescent protein moiety to maximize the overlap integral J. Also, the quantum yield of the donor fluorescent protein moiety and the extinction coefficient of the acceptor fluorescent protein moiety should be as large as possible to maximize R₀. In addition, the excitation spectra of the donor and acceptor moieties should overlap as little as possible so that a wavelength region can be found at which the donor moiety can be excited selectively and efficiently without directly exciting the acceptor moiety. Direct excitation of the acceptor moiety should be avoided since it can be difficult to distinguish direct emission from fluorescence arising from FRET. Similarly, the emission spectra of the donor and acceptor moieties should have minimal overlap so that the two emissions can be distinguished. High fluorescence quantum yield of the acceptor moiety is desirable if the emission from the acceptor moiety is to be monitored to determine analyte concentration in a sample. In a preferred embodiment, the donor fluorescent protein moiety is excited by ultraviolet (<400 nm) and emits blue light (<500 nm), and the acceptor fluorescent protein moiety is efficiently excited by blue but not by ultraviolet light and emits green light (>500 nm), for example, P4-3 and S65T, respectively.

In another preferred embodiment, the donor fluorescent moiety is excited by violet (400-430 nm) and emits blue-green (450-500 nm) and the acceptor fluorescent moiety is efficiently excited by blue-green (450-500 nm) and emits yellow-green light (≧520 nm), for example WIB and 10C respectively.

The amount of analyte in a sample can be determined by determining the degree of FRET in the sample. Changes in analyte concentration can be determined by monitoring FRET at a first and second time after contact between the sample and the fluorescent indicator and determining the difference in the degree of FRET. The amount of analyte in the sample can be calculated by using a calibration curve established by titration.

The degree of FRET can be determined by any spectral or fluorescence lifetime characteristic of the excited donor moiety. For example, intensity of the fluorescent signal from the donor, the intensity of fluorescent signal from the acceptor, the ratio of the fluorescence amplitudes near the acceptor's emission maxima to the fluorescence amplitudes near the donor's emission maximum, or the excited state lifetime of the donor can be monitored.

Preferably, changes in the degree of FRET are determined as a function of the change in the ratio of the amount of fluorescence from the donor and acceptor moieties, a process referred to as "ratioing." Changes in the absolute amount of indicator, excitation intensity, and turbidity or other background absorbances in the sample at the excitation wavelength affect the intensities of fluorescence from both the donor and acceptor approximately in parallel. Therefore the ratio of the two emission intensities is a more robust and preferred measure of cleavage than either intensity alone.

Fluorescence in a sample is measured using a fluorometer. In general, excitation radiation, from an excitation source having a first wavelength, passes through excitation optics. The excitation optics cause the excitation radiation to excite the sample. In response, fluorescent proteins in the sample emit radiation which has a wavelength that is different from the excitation wavelength. Collection optics then collect the emission from the sample. The device can include a temperature controller to maintain the sample at a specific temperature while it is being scanned. According to one embodiment, a multi-axis translation stage moves a microtiter plate holding a plurality of samples in order to position different wells to be exposed. The multi-axis translation stage, temperature controller, auto-focusing feature, and electronics associated with imaging and data collection can be managed by an appropriately programmed digital computer. The computer also can transform the data collected during the assay into another format for presentation.

Methods of performing assays on fluorescent materials are well known in the art and are described in, e.g., Lakowicz, J. R., Principles of Fluorescence Spectroscopy, New York:Plenum Press (1983); Herman, B., Resonance energy transfer microscopy, in: Fluorescence Microscopy of Living Cells in Culture, Part B, Methods in Cell Biology, vol. 30, ed. Taylor, D. L. & Wang, Y.-L., San Diego: Academic Press (1989), pp. 219-243; Turro, N. J., Modern Molecular Photochemistry, Menlo Park: Benjamin/Cummings Publishing Col, Inc. (1978), pp. 296-361.

The excited state lifetime of the donor moiety is, likewise, independent of the absolute amount of substrate, excitation intensity, or turbidity or other background absorbances. Its measurement requires equipment with nanosecond time resolution.

Quantum yields of wild-type GFP, S65T, and P4-1 mutants can be estimated by comparison with fluorescein in 0.1 N NaOH as a standard of quantum yield 0.91. J. N. Miller, ed., Standards in Fluorescence Spectrometry, New York: Chapman and Hall (1981). Mutants P4 and P4-3 were likewise compared to 9-aminoacridine in water (quantum yield 0.98).

Any fluorescent protein can be used in the invention, including proteins that fluoresce due intramolecular rearrangements or the addition of cofactors that promote fluorescence. For example, green fluorescent proteins of cnidarians, which act as their energy-transfer acceptors in bioluminescence, are suitable fluorescent proteins for use in the fluorescent indicators. A green fluorescent protein ("GFP") is a protein that emits green light, and a blue fluorescent protein ("BFP") is a protein that emits blue light. GFPs have been isolated from the Pacific Northwest jellyfish, Aequorea victoria, the sea pansy, Renilla reniformis, and Phialidium gregarium. See, Ward, W. W., et al., Photochem. Photobiol., 35:803-808 (1982); and Levine, L. D., et al., Comp. Biochem. Physiol., 72B:77-85 (1982).

A variety of Aequorea-related GFPs having useful excitation and emission spectra have been engineered by modifying the amino acid sequence of a naturally occurring GFP from Aequorea victoria. See, Prasher, D. C., et al., Gene, 111:229-233 (1992); Heim, R., et al., Proc. Natl. Acad. Sci., USA, 91:12501-04 (1994); U.S. Pat. No. 5,625,048; International application PCT/US95/14692, filed Nov. 10, 1995; and U.S. Ser. No. 08/706,408, filed Aug. 30, 1996. The cDNA of GFP can be concatenated with those encoding many other proteins; the resulting fusions often are fluorescent and retain the biochemical features of the partner proteins. See, Cubitt, A. B., et al., Trends Biochem. Sci. 20:448-455 (1995). Mutagenesis studies have produced GFP mutants with shifted wavelengths of excitation or emission. See, Heim, R. & Tsien, R. Y. Current Biol. 6:178-182 (1996). Suitable pairs, for example a blue-shifted GFP mutant P4-3 (Y66H/Y145F) and an improved green mutant S65T can respectively serve as a donor and an acceptor for fluorescence resonance energy transfer (FRET). See, Tsien, R. Y., et al., Trends Cell Biol. 3:242-245 (1993). A fluorescent protein is an Aequorea-related fluorescent protein if any contiguous sequence of 150 amino acids of the fluorescent protein has at least 85% sequence identity with an amino acid sequence, either contiguous or non-contiguous, from the wild type Aequorea green fluorescent protein. More preferably, a fluorescent protein is an Aequorea-related fluorescent protein if any contiguous sequence of 200 amino acids of the fluorescent protein has at least 95% sequence identity with an amino acid sequence, either contiguous or non-contiguous, from the wild type Aequorea green fluorescent protein. Similarly, the fluorescent protein can be related to Renilla or Phialidium wild-type fluorescent proteins using the same standards. Some Aequorea-related engineered versions described in Table I. Other variants or mutants are within the scope of the invention as described, for example, in the Examples.

                                      TABLE I                                      __________________________________________________________________________                              Extinction                                                                                Excitation Emission Coefficient                                             Quantum                                         Clone Mutation(s) max (nm) max (nm) (M                                                                        .sup.-1 cm.sup.-1) yield                      __________________________________________________________________________     Wild type                                                                            none   395 (475)                                                                            508   21,000 (7,150)                                                                         0.77                                            P4 Y66H 383 447 13,500 0.21                                                    P4-3 Y66H;Y145F 381 445 14,000 0.38                                            W7 Y66W;N146I 433 (453) 475 (501) 18,000 (17,100) 0.67                          M153T                                                                          V163A                                                                          N212K                                                                         W2 Y66W;I123V 432 (453) 480 10,000 (9,600) 0.72                                 Y145H                                                                          H148R                                                                          M153T                                                                          V163A                                                                          N212K                                                                         S65T 865T 489 511 39,200 0.68                                                  P4-1 S65T;M153A 504 (396) 514 14,500 (8,600) 0.53                               K238E                                                                         S65A S65A 471 504                                                              S65C S65C 479 507                                                              S6SL S65L 484 510                                                              Y66F Y66F 36Q 442                                                              Y66W Y66W 458 480                                                              10c S6SG;V68L 513 527                                                           S72A;T203Y                                                                    W1B F64L;S65T 432 (453) 476 (503)                                               Y66W;N146I                                                                     M153T                                                                          V163A                                                                          N212K                                                                         Emerald S65T;S72A 487 508                                                       N149K                                                                          M153T                                                                          I167T                                                                         Sapphire S72A;Y145F 395 511                                                     T2031                                                                       __________________________________________________________________________

An additional clone, W1B1 included the following mutations: F64L;S65T; Y66W; F99S; and V163A.

Other fluorescent proteins can be used in the fluorescent indicators, such as, for example, yellow fluorescent protein from Vibrio fischeri strain Y-1, Peridinin-chlorophyll a binding protein from the dinoflagellate Symbiodinium sp.phycobiliproteins from marine cyanobacteria such as Synechococcus, e.g., phycoerythrin and phycocyanin, or oat phytochromes from oat reconstructed with phycoerythrobilin. These fluorescent proteins have been described in Baldwin, T. O., et al., Biochemistry 29:5509-5515 (1990), Morris, B. J., et al., Plant Molecular Biology, 24:673-677 (1994), and Wilbanks, S. M., et al., J. Biol. Chem. 268:1226-1235 (1993), and Li et al., Biochemistry 34:7923-7930 (1995).

The efficiency of FRET between the donor and acceptor fluorescent protein moieties can be adjusted by changing ability of the two fluorescent proteins to closely associate. The nature of the binding protein moiety, target peptide moiety, and linker moiety each affect the FRET and the response of the indicator to the analyte. Generally, large conformational changes in the binding protein moiety are desired along with a high affinity for the target peptide moiety.

The binding protein moiety is a protein, or part thereof, that changes conformation upon binding an analyte. Proteins that undergo useful conformation change upon binding an analyte include calmodulin (CaM), cGMP-dependent protein kinase, steroid hormone receptors (or ligand binding domain thereof), protein kinase C, inositol-1,4,5-triphosphate receptor, or recoverin. See, for example, Katzenellenbogen, J. A. & Katzenellenbogen, B. S. Chemistry & Biology 3:529-536 (1996), and Ames, J. B., et al., Curr. Opin. Struct. Biol. 6:432-438 (1996). The binding protein moiety preferably binds target peptides in addition to the analyte. The Ca²⁺ -binding affinity of calmodulin can be tuned as reviewed, for example, in Falke, J. J., et al., Quart. Rev. Biophys. 27:219-290 (1994).

The target peptide moiety can contain any of the amino acid sequences in Table II, or a portion thereof with the proviso that the target peptide must bind to the binding protein moiety. The target peptide can be a subsequence of a calmodulin-binding domain. The target peptide moieties listed in Table II are recognized by the binding protein moiety CaM. See, for example, Crivici, A. & Ikura, M. Annu. Rev. Biophys. Biomol. Struct. 24:84-116 (1995). The target peptide moiety can be modified to enhance the response of the fluorescent indicator to the analyte. Other target peptide moieties are known in the art for other binding proteins.

                                      TABLE II                                     __________________________________________________________________________     Target.sup.a            Sequence                                               __________________________________________________________________________     SkMLCK (M13)   (SEQ ID NO:9)                                                                                KRRWKKNFIAVSAANRFKKISSSGAL                           - smMLCK (smMLCKp) (SEQ ID NO:10)     ARRKWQKTGHAVRAIGRLSS                     - CaMKII (SEQ ID NO:11)     ARRKLKGAILTTMLATRNFS                               - Caldesmon (SEQ ID NO:12)        GVRNIKSMWEKGNVFSS                            - Calspermin (SEQ ID NO:13)     ARRKLKAAVKAVVASSRLGS                           - PFK (M11) (SEQ ID NO:14)    FMNNWEVYKLLAHIRPPAPKSGSYTV                       - Calcineurin (SEQ ID NO:15)      ARKEVIRNKIRAIGKMARVFSVLR                     - PhK (PhK5) (SEQ ID NO:16)         LRRLIDAYAFRIYGHWVKKGQQQNRG                                                             -   (PhKl3) (SEQ ID NO:17)                                                          RGKFKVICLTVLASVRIYYQYR                                                  RVKPG                                - Ca.sup.2+ -ATPase (C28W) (SEQ ID NO:18)    LRRGQILWFRGLNRIQTQIKVVNAFS                                                  SS                                   - 59-kDa PDE (SEQ ID NO:19)       RRKHLQRPIFRLRCLVKQLEK                        - 60-kDa PDE (SEQ ID NO:20)       TEKMWQRLKGILRCLVKQLEK                        - NOS (NO-30) (SEQ ID NO:21)     KRRAIGFKKLAEAVKFSAKLMGQ                       - Type I AC (AC-28) (SEQ ID NO:22)   IKPAKRMKFKTVCYLLVQLMHCRKMFKA                                                          - Borderella periussus AC                                                    (SEQ ID NO:23)                                                                 IDLLWKIARAGARSAVGTEA                                                             - Neuromodulin (SEQ ID                                                       NO:24)   KAHKAATKIQASFRGHITRK                                                  KLKGEKK                              - Spectrin (SEQ ID NO:25)      KTASPWKSARLMVHTVATFNSIKE                        - MARCKS (SEQ ID NO:26)     KKKKKRFSFKKSFKLSGFSFKKSKK                          - F52 or MacMARKS (SEQ ID NO:27)      KKKKKFSFKKPFKLSGLSFKRNRK                                                             - β-Adducin (SEQ ID                                                     NO:28)   KQQKEKTRWLNTPNTYLRVN                                                  VADEVQRNMGS                          - HSP90a (SEQ ID NO:29)        KDQVANSAFQERLRKHGLEVI                           - HIV-1 gp160 (SEQ ID NO:30)           YHRLRDLLLIVKRIVELLGRR                   - BBMHBI (SEQ ID NO:31)     QQLATLIQKTYRGWRCRTHYQLM                            - Dilute MHC (SEQ ID NO:32)     RAACIRIQKTIRGWLLRKRYLCMQ                       - Mastoparan (SEQ ID NO:33)           INLKALAALAKKIL                           - Melittin (SEQ ID NO:34)      GIGAVLKVLTTGLPALISWIKRKRQQ                      - Glucagon (SEQ ID NO:35) HSQGTFTTSDYSKYLDSRRAQDFVQWLMNT                       - Secretin (SEQ ID NO:36)  HSDGTFTSELSRLRDSARLQRLLQGLV                         - VIP (SEQ ID NO:37)  HSDAVFTDNYTRLRKQMAVKKYLNSILN                             - GIP (SEQ ID NO:38)  YADGTFISDYSAIMNKIRQQDFVNWLLAQQQKS                        - Model Peptide CBP2 (SEQ ID NO:39)         KLWKKLLKLLKKLLKLG               __________________________________________________________________________      .sup.a Abbreviations: AC, adenylyl cyclase; BBMHCI, brush border myosin        heavy chainI; CaMKII, calmodulin kinase II; CBP2, calmodulin binding           peptide2; GIP, gastrin inhibitory peptide; HIV1 gpl60, human                   immunodeficiency virus envelope glycoprotein 160; HSP, heatshock protein;      MARCKS, myristoylated alaminterich C kinase substrate; MHC, myosin heavy       chain; NOS, nitric oxide synthase; PDE,phosphodiesterase; PFK,                 phosphofructokinase; PhK, phosphorylase kinase; sk,  # smMLCK, skeletal        muscle and smooth musclemyosin light chain kinase; VIP vasoactive              intestinal peptide.                                                      

The length of the linker moiety is chosen to optimize both FRET and the kinetics and specificity of conformational changes induced by analyte binding. The linker moiety should be long enough and flexible enough to allow the binding protein moiety and target peptide moiety to freely interact and respond to analyte concentration. In order to optimize the FRET effect, the average distance between the donor and acceptor fluorescent protein moieties should become between about 1 nm and about 10 nm, preferably between about 1 nm and about 6 nm, and more preferably between about 1 nm and about 4 nm, when the analyte is bound (or released). If the linker is too short or too stiff, the donor and acceptor protein moieties cannot readily change position. If the linker moiety is too long, the target peptide moiety might not bind to the binding protein moiety effectively. The linker moiety is, preferably, a peptide moiety. The preferred linker moiety is a peptide between about one and 30 amino acid residues in length, preferably between about two and 15 amino acid residues. One preferred linker moiety is a --Gly-Gly-- linker.

The linker moiety can include flexible spacer amino acid sequences, such as those known in single-chain antibody research. For example, the linker moiety can be GGGGS (SEQ ID NO:40) (GGGGS)_(n), GKSSGSGSESKS (SEQ ID NO:41), GSTSGSGKSSEGKG (SEQ ID NO:42), GSTSGSGKSSEGSGSTKG (SEQ ID NO:43), GSTSGSGKSSEGKG (SEQ ID NO:44), GSTSGSGKPGSGEGSTKG (SEQ ID NO:45), or EGKSSGSGSESKEF (SEQ ID NO:46). Linking moieties are described, for example, in Huston, J. S., et al., PNAS 85:5879-5883 (1988), Whitlow, M., et al., Protein Engineering 6:989-995 (1993), and Newton, D. L., et al., Biochemistry 35:545-553 (1996).

The fluorescent indicators can also include a localization sequence to direct the indicator to particular cellular sites by fusion to appropriate organellar targeting signals or localized host proteins. A polynucleotide encoding a localization sequence, or signal sequence, can be ligated or fused at the 5' terminus of a polynucleotide encoding the fluorescence indicator such that the signal peptide is located at the amino terminal end of the resulting fusion polynucleotide/polypeptide. In the case of eukaryotes, the signal peptide is believed to function to transport the fusion polypeptide across the endoplasmic reticulum. The secretory protein is then transported through the Golgi apparatus, into secretory vesicles and into the extracellular space or, preferably, the external environment. Signal peptides which can be utilized according to the invention include pre-pro peptides which contain a proteolytic enzyme recognition site. Other signal peptides with similar properties to pro-calcitonin described herein are known to those skilled in the art, or can be readily ascertained without undue experimentation.

The localization sequence can be a nuclear localization sequence, an endoplasmic reticulum localization sequence, a peroxisome localization sequence, a mitochondrial localization sequence, or a localized protein. Localization sequences can be targeting sequences which are described, for example, in "Protein Targeting", chapter 35 of Stryer, L., Biochemistry (4th ed.). W. H. Freeman, 1995. The localization sequence can also be a localized protein. Some important localization sequences include those targeting the nucleus (KKKRK) (SEQ ID NO:47), mitochondrion (amino terminal MLRTSSLFTRRVQPSLFRNILRLQST-(SEQ ID NO:48)), endoplasmic reticulum (KDEL (SEQ ID NO:49) at C-terminus, assuming a signal sequence present at N-terminus), peroxisome (SKF (SEQ ID NO:50) at C-terminus), prenylation or insertion into plasma membrane (CaaX (SEQ ID NO:51), CC (SEQ ID NO:52), CXC (SEQ ID NO:53), or CCXX (SEQ ID NO:54) at C-terminus), cytoplasmic side of plasma membrane (fusion to SNAP-25), or the Golgi apparatus (fusion to furin).

The fluorescent indicators can be produced as fusion proteins by recombinant DNA technology. Recombinant production of fluorescent proteins involves expressing nucleic acids having sequences that encode the proteins. Nucleic acids encoding fluorescent proteins can be obtained by methods known in the art. For example, a nucleic acid encoding the protein can be isolated by polymerase chain reaction of cDNA from A. victoria using primers based on the DNA sequence of A. victoria green fluorescent protein. PCR methods are described in, for example, U.S. Pat. No. 4,683,195; Mullis, et al. Cold Spring Harbor Symp. Quant. Biol. 51:263 (1987), and Erlich, ed., PCR Technology, (Stockton Press, N.Y., 1989). Mutant versions of fluorescent proteins can be made by site-specific mutagenesis of other nucleic acids encoding fluorescent proteins, or by random mutagenesis caused by increasing the error rate of PCR of the original polynucleotide with 0.1 mM MnCl₂ and unbalanced nucleotide concentrations. See, e.g., U.S. Pat. No. 5,625,048 or International application PCT/US95/14692, filed Nov. 10, 1994.

The construction of expression vectors and the expression of genes in transfected cells involves the use of molecular cloning techniques also well known in the art. Sambrook et al., Molecular Cloning--A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., (1989) and Current Protocols in Molecular Biology, F. M. Ausubel et al., eds., (Current Protocols, a joint venture between Greene Publishing Associates, Inc. and John Wiley & Sons, Inc., most recent Supplement).

Nucleic acids used to transfect cells with sequences coding for expression of the polypeptide of interest generally will be in the form of an expression vector including expression control sequences operatively linked to a nucleotide sequence coding for expression of the polypeptide. As used, the term "nucleotide sequence coding for expression of" a polypeptide refers to a sequence that, upon transcription and translation of mRNA, produces the polypeptide. This can include sequences containing, e.g., introns. As used herein, the term "expression control sequences" refers to nucleic acid sequences that regulate the expression of a nucleic acid sequence to which it is operatively linked. Expression control sequences are operatively linked to a nucleic acid sequence when the expression control sequences control and regulate the transcription and, as appropriate, translation of the nucleic acid sequence. Thus, expression control sequences can include appropriate promoters, enhancers, transcription terminators, a start codon (i.e., ATG) in front of a protein-encoding gene, splicing signals for introns, maintenance of the correct reading frame of that gene to permit proper translation of the mRNA, and stop codons.

Methods which are well known to those skilled in the art can be used to construct expression vectors containing the fluorescent indicator coding sequence and appropriate transcriptional/translational control signals. These methods include in vitro recombinant DNA techniques, synthetic techniques and in vivo recombination/genetic recombination. (See, for example, the techniques described in Maniatis, et al., Molecular Cloning A Laboratory Manual, Cold Spring Harbor Laboratory, N.Y., 1989).

Transformation of a host cell with recombinant DNA may be carried out by conventional techniques as are well known to those skilled in the art. Where the host is prokaryotic, such as E. coli, competent cells which are capable of DNA uptake can be prepared from cells harvested after exponential growth phase and subsequently treated by the CaCl₂ method by procedures well known in the art. Alternatively, MgCl₂ or RbCl can be used. Transformation can also be performed after forming a protoplast of the host cell or by electroporation.

When the host is a eukaryote, such methods of transfection of DNA as calcium phosphate co-precipitates, conventional mechanical procedures such as microinjection, electroporation, insertion of a plasmid encased in liposomes, or virus vectors may be used. Eukaryotic cells can also be cotransfected with DNA sequences encoding the fusion polypeptide of the invention, and a second foreign DNA molecule encoding a selectable phenotype, such as the herpes simplex thymidine kinase gene. Another method is to use a eukaryotic viral vector, such as simian virus 40 (SV40) or bovine papilloma virus, to transiently infect or transform eukaryotic cells and express the protein. (Eukaryotic Viral Vectors, Cold Spring Harbor Laboratory, Gluzman ed., 1982). Preferably, a eukaryotic host is utilized as the host cell as described herein.

Techniques for the isolation and purification of either microbially or eukaryotically expressed polypeptides of the invention may be by any conventional means such as, for example, preparative chromatographic separations and immunological separations such as those involving the use of monoclonal or polyclonal antibodies or antigen.

A variety of host-expression vector systems may be utilized to express fluorescent indicator coding sequence. These include but are not limited to microorganisms such as bacteria transformed with recombinant bacteriophage DNA, plasmid DNA or cosmid DNA expression vectors containing a fluorescent indicator coding sequence; yeast transformed with recombinant yeast expression vectors containing the fluorescent indicator coding sequence; plant cell systems infected with recombinant virus expression vectors (e.g., cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or transformed with recombinant plasmid expression vectors (e.g., Ti plasmid) containing a fluorescent indicator coding sequence; insect cell systems infected with recombinant virus expression vectors (e.g., baculovirus) containing a fluorescent indicator coding sequence; or animal cell systems infected with recombinant virus expression vectors (e.g., retroviruses, adenovirus, vaccinia virus) containing a fluorescent indicator coding sequence, or transformed animal cell systems engineered for stable expression.

Depending on the host/vector system utilized, any of a number of suitable transcription and translation elements, including constitutive and inducible promoters, transcription enhancer elements, transcription terminators, etc. may be used in the expression vector (see, e.g., Bitter, et al., Methods in Enzymology 153:516-544, 1987). For example, when cloning in bacterial systems, inducible promoters such as pL of bacteriophage λ, plac, ptrp, ptac (ptrp-lac hybrid promoter) and the like may be used. When cloning in mammalian cell systems, promoters derived from the genome of mammalian cells (e.g., metallothionein promoter) or from mammalian viruses (e.g., the retrovirus long terminal repeat; the adenovirus late promoter; the vaccinia virus 7.5K promoter) may be used. Promoters produced by recombinant DNA or synthetic techniques may also be used to provide for transcription of the inserted fluorescent indicator coding sequence.

In bacterial systems a number of expression vectors may be advantageously selected depending upon the use intended for the fluorescent indicator expressed. For example, when large quantities of the fluorescent indicator are to be produced, vectors which direct the expression of high levels of fusion protein products that are readily purified may be desirable. Those which are engineered to contain a cleavage site to aid in recovering fluorescent indicator are preferred.

In yeast, a number of vectors containing constitutive or inducible promoters may be used. For a review see, Current Protocols in Molecular Biology, Vol. 2, Ed. Ausubel, et al., Greene Publish. Assoc. & Wiley Interscience, Ch. 13, 1988; Grant, et al., Expression and Secretion Vectors for Yeast, in Methods in Enzymology, Eds. Wu & Grossman, 31987, Acad. Press, N.Y., Vol. 153, pp.516-544, 1987; Glover, DNA Cloning, Vol. II, IRL Press, Wash., D.C., Ch. 3, 1986; and Bitter, Heterologous Gene Expression in Yeast, Methods in Enzymology, Eds. Berger & Kimmel, Acad. Press, N.Y., Vol. 152, pp. 673-684, 1987; and The Molecular Biology of the Yeast Saccharomyces, Eds. Strathern et al., Cold Spring Harbor Press, Vols. I and II, 1982. A constitutive yeast promoter such as ADH or LEU2 or an inducible promoter such as GAL may be used (Cloning in Yeast, Ch. 3, R. Rothstein In: DNA Cloning Vol.11, A Practical Approach, Ed. DM Glover, IRL Press, Wash., D.C., 1986). Alternatively, vectors may be used which promote integration of foreign DNA sequences into the yeast chromosome.

In cases where plant expression vectors are used, the expression of a fluorescent indicator coding sequence may be driven by any of a number of promoters. For example, viral promoters such as the 35S RNA and 19S RNA promoters of CaMV (Brisson, et al., Nature 310:511-514, 1984), or the coat protein promoter to TMV (Takamatsu, et al., EMBO J. 6:307-311, 1987) may be used; alternatively, plant promoters such as the small subunit of RUBISCO (Coruzzi, et al., 1984, EMBO J. 3:1671-1680; Broglie, et al., Science 224:838-843, 1984); or heat shock promoters, e.g., soybean hsp17.5-E or hsp17.3-B (Gurley, et al., Mol. Cell. Biol. 6:559-565, 1986) may be used. These constructs can be introduced into plant cells using Ti plasmids, Ri plasmids, plant virus vectors, direct DNA transformation, microinjection, electroporation, etc. For reviews of such techniques see, for example, Weissbach & Weissbach, Methods for Plant Molecular Biology, Academic Press, N.Y., Section VIII, pp. 421-463, 1988; and Grierson & Corey, Plant Molecular Biology, 2d Ed., Blackie, London, Ch. 7-9, 1988.

An alternative expression system which could be used to express fluorescent indicator is an insect system. In one such system, Autographa californica nuclear polyhedrosis virus (AcNPV) is used as a vector to express foreign genes. The virus grows in Spodoptera frugiperda cells. The fluorescent indicator coding sequence may be cloned into non-essential regions (for example, the polyhedrin gene) of the virus and placed under control of an AcNPV promoter (for example the polyhedrin promoter). Successful insertion of the fluorescent indicator coding sequence will result in inactivation of the polyhedrin gene and production of non-occluded recombinant virus (i.e., virus lacking the proteinaceous coat coded for by the polyhedrin gene). These recombinant viruses are then used to infect Spodoptera frugiperda cells in which the inserted gene is expressed, see Smith, et al., J. Viol. 46:584, 1983; Smith, U.S. Pat. No. 4,215,051.

Eukaryotic systems, and preferably mammalian expression systems, allow for proper post-translational modifications of expressed mammalian proteins to occur. Eukaryotic cells which possess the cellular machinery for proper processing of the primary transcript, glycosylation, phosphorylation, and, advantageously secretion of the gene product should be used as host cells for the expression of fluorescent indicator. Such host cell lines may include but are not limited to CHO, VERO, BHK, HeLa, COS, MDCK, Jurkat, HEK-293, and WI38.

Mammalian cell systems which utilize recombinant viruses or viral elements to direct expression may be engineered. For example, when using adenovirus expression vectors, the fluorescent indicator coding sequence may be ligated to an adenovirus transcription/translation control complex, e.g., the late promoter and tripartite leader sequence. This chimeric gene may then be inserted in the adenovirus genome by in vitro or in vivo recombination. Insertion in a non-essential region of the viral genome (e.g., region E1 or E3) will result in a recombinant virus that is viable and capable of expressing the fluorescent indicator in infected hosts (e.g., see Logan & Shenk, Proc. Natl. Acad. Sci. USA, 81: 3655-3659, 1984). Alternatively, the vaccinia virus 7.5K promoter may be used. (e.g., see, Mackett, et al., Proc. Natl. Acad. Sci. USA, 79: 7415-7419, 1982; Mackett, et al., J. Virol. 49: 857-864, 1984; Panicali, et al., Proc. Natl. Acad. Sci. USA 79: 4927-4931, 1982). Of particular interest are vectors based on bovine papilloma virus which have the ability to replicate as extrachromosomal elements (Sarver, et al., Mol. Cell. Biol. 1: 486, 1981). Shortly after entry of this DNA into mouse cells, the plasmid replicates to about 100 to 200 copies per cell. Transcription of the inserted cDNA does not require integration of the plasmid into the host's chromosome, thereby yielding a high level of expression. These vectors can be used for stable expression by including a selectable marker in the plasmid, such as the neo gene. Alternatively, the retroviral genome can be modified for use as a vector capable of introducing and directing the expression of the fluorescent indicator gene in host cells (Cone & Mulligan, Proc. Natl. Acad. Sci. USA, 81:6349-6353, 1984). High level expression may also be achieved using inducible promoters, including, but not limited to, the metallothionine IIA promoter and heat shock promoters.

For long-term, high-yield production of recombinant proteins, stable expression is preferred. Rather than using expression vectors which contain viral origins of replication, host cells can be transformed with the fluorescent indicator cDNA controlled by appropriate expression control elements (e.g., promoter, enhancer, sequences, transcription terminators, polyadenylation sites, etc.), and a selectable marker. The selectable marker in the recombinant plasmid confers resistance to the selection and allows cells to stably integrate the plasmid into their chromosomes and grow to form foci which in turn can be cloned and expanded into cell lines. For example, following the introduction of foreign DNA, engineered cells may be allowed to grow for 1-2 days in an enriched media, and then are switched to a selective media. A number of selection systems may be used, including but not limited to the herpes simplex virus thymidine kinase (Wigler, et al., Cell, 11: 223, 1977), hypoxanthine-guanine phosphoribosyltransferase (Szybalska & Szybalski, Proc. Natl. Acad. Sci. USA, 48:2026, 1962), and adenine phosphoribosyltransferase (Lowy, et al., Cell, 22: 817, 1980) genes can be employed in tk⁻, hgprt⁻ or aprt⁻ cells respectively. Also, antimetabolite resistance can be used as the basis of selection for dhfr, which confers resistance to methotrexate (Wigler, et al., Proc. Natl. Acad. Sci. USA, 77: 3567, 1980; O'Hare, et al., Proc. Natl. Acad. Sci. USA, 8: 1527, 1981); gpt, which confers resistance to mycophenolic acid (Mulligan & Berg, Proc. Natl. Acad. Sci. USA, 78: 2072, 1981; neo, which confers resistance to the aminoglycoside G-418 (Colberre-Garapin, et al., J. Mol. Biol., 150:1, 1981); and hygro, which confers resistance to hygromycin (Santerre, et al., Gene, 30: 147, 1984) genes. Recently, additional selectable genes have been described, namely trpB, which allows cells to utilize indole in place of tryptophan; hisD, which allows cells to utilize histinol in place of histidine (Hartman & Mulligan, Proc. Natl. Acad. Sci. USA, 85:8047, 1988); and ODC (ornithine decarboxylase) which confers resistance to the ornithine decarboxylase inhibitor, 2-(difluoromethyl)-DL-ornithine, DFMO (McConlogue L., In: Current Communications in Molecular Biology, Cold Spring Harbor Laboratory, ed., 1987).

DNA sequences encoding the fluorescence indicator polypeptide of the invention can be expressed in vitro by DNA transfer into a suitable host cell. "Host cells" are cells in which a vector can be propagated and its DNA expressed. The term also includes any progeny of the subject host cell. It is understood that all progeny may not be identical to the parental cell since there may be mutations that occur during replication. However, such progeny are included when the term "host cell" is used. Methods of stable transfer, in other words when the foreign DNA is continuously maintained in the host, are known in the art.

Recombinant fluorescent protein can be produced by expression of nucleic acid encoding the protein in prokaryotes, such as E. coli or in eukaryotes, such as yeast cells or mammalian cells. The fluorophore of Aequorea-related fluorescent proteins results from cyclization and oxidation of residues 65-67.

The construct can also contain a tag to simplify isolation of the fluorescent indicator. For example, a polyhistidine tag of, e.g., six histidine residues, can be incorporated at the amino terminal end of the fluorescent protein. The polyhistidine tag allows convenient isolation of the protein in a single step by nickel-chelate chromatography.

In a preferred embodiment, the fluorescent indicator is a fusion protein produced by recombinant DNA technology in which a single polypeptide includes a donor moiety, a peptide linker moiety and an acceptor moiety. The donor moiety can be positioned at the amino-terminus relative to the acceptor moiety in the polypeptide. Such a fusion protein has the generalized structure: (amino terminus) donor fluorescent protein moiety--peptide linker moiety--acceptor fluorescent protein moiety (carboxy terminus). Alternatively, the donor moiety can be positioned at the carboxy-terminus relative to the acceptor moiety within the fusion protein. Such a fusion protein has the generalized structure: (amino terminus) acceptor fluorescent protein moiety--peptide linker moiety--donor fluorescent protein moiety (carboxy terminus). The invention also envisions fusion proteins that contain extra amino acid sequences at the amino and/or carboxy termini, for example, polyhistidine tags.

Thus, fluorescent indicators encoded by a recombinant nucleic acid include sequences coding for expression of a donor fluorescent protein moiety, an acceptor fluorescent protein moiety and a peptide linker moiety. The elements are selected so that upon expression into a fusion protein, the donor and acceptor moieties exhibit FRET when the donor moiety is excited. The recombinant nucleic acid can be incorporated into an expression vector comprising expression control sequences operatively linked to the recombinant nucleic acid. The expression vector can be adapted for function in prokaryotes or eukaryotes by inclusion of appropriate promoters, replication sequences, markers, etc.

The expression vector can be transfected into a host cell for expression of the recombinant nucleic acid. Host cells can be selected for high levels of expression in order to purify the fluorescent indicator fusion protein. E. coli is useful for this purpose. Alternatively, the host cell can be a prokaryotic or eukaryotic cell selected to study the activity of an enzyme produced by the cell. In this case, the linker peptide is selected to include an amino acid sequence recognized by the protease. The cell can be, e.g., a cultured cell or a cell in vivo.

A primary advantage of fluorescent indicator fusion proteins is that they are prepared by normal protein biosynthesis, thus completely avoiding organic synthesis and the requirement for customized unnatural amino acid analogs. The constructs can be expressed in E. coli in large scale for in vitro assays. Purification from bacteria is simplified when the sequences include polyhistidine tags for one-step purification by nickel-chelate chromatography. Alternatively, the substrates can be expressed directly in a desired host cell for assays in situ.

In another embodiment, the invention provides a transgenic non-human animal that expresses a nucleic acid sequence which encodes the fluorescent indicator.

The "non-human animals" of the invention comprise any non-human animal having nucleic acid sequence which encodes a fluorescent indicator. Such non-human animals include vertebrates such as rodents, non-human primates, sheep, dog, cow, pig, amphibians, and reptiles. Preferred non-human animals are selected from the rodent family including rat and mouse, most preferably mouse. The "transgenic non-human animals" of the invention are produced by introducing "transgenes" into the germline of the non-human animal. Embryonal target cells at various developmental stages can be used to introduce transgenes. Different methods are used depending on the stage of development of the embryonal target cell. The zygote is the best target for micro-injection. In the mouse, the male pronucleus reaches the size of approximately 20 micrometers in diameter which allows reproducible injection of 1-2 pl of DNA solution. The use of zygotes as a target for gene transfer has a major advantage in that in most cases the injected DNA will be incorporated into the host gene before the first cleavage (Brinster et al., Proc. Natl. Acad. Sci. USA 82:4438-4442, 1985). As a consequence, all cells of the transgenic non-human animal will carry the incorporated transgene. This will in general also be reflected in the efficient transmission of the transgene to offspring of the founder since 50% of the germ cells will harbor the transgene. Microinjection of zygotes is the preferred method for incorporating transgenes in practicing the invention.

The term "transgenic" is used to describe an animal which includes exogenous genetic material within all of its cells. A "transgenic" animal can be produced by cross-breeding two chimeric animals which include exogenous genetic material within cells used in reproduction. Twenty-five percent of the resulting offspring will be transgenic i.e., animals which include the exogenous genetic material within all of their cells in both alleles. 50% of the resulting animals will include the exogenous genetic material within one allele and 25% will include no exogenous genetic material.

Retroviral infection can also be used to introduce transgene into a non-human animal. The developing non-human embryo can be cultured in vitro to the blastocyst stage. During this time, the blastomeres can be targets for retro viral infection (Jaenich, R., Proc. Natl. Acad. Sci USA 73:1260-1264, 1976). Efficient infection of the blastomeres is obtained by enzymatic treatment to remove the zona pellucida (Hogan, et al. (1986) in Manipulating the Mouse Embryo, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.). The viral vector system used to introduce the transgene is typically a replication-defective retro virus carrying the transgene (Jahner, et al., Proc. Natl. Acad. Sci. USA 82:6927-6931, 1985; Van der Putten, et al., Proc. Natl. Acad. Sci USA 82:6148-6152, 1985). Transfection is easily and efficiently obtained by culturing the blastomeres on a monolayer of virus-producing cells (Van der Putten, supra; Stewart, et al., EMBO J. 6:383-388, 1987). Alternatively, infection can be performed at a later stage. Virus or virus-producing cells can be injected into the blastocoele (D. Jahner et al., Nature 298:623-628, 1982). Most of the founders will be mosaic for the transgene since incorporation occurs only in a subset of the cells which formed the transgenic nonhuman animal. Further, the founder may contain various retro viral insertions of the transgene at different positions in the genome which generally will segregate in the offspring. In addition, it is also possible to introduce transgenes into the germ line, albeit with low efficiency, by intrauterine retro viral infection of the midgestation embryo (D. Jahner et al., supra).

A third type of target cell for transgene introduction is the embryonal stem cell (ES). ES cells are obtained from pre-implantation embryos cultured in vitro and fused with embryos (M. J. Evans et al. Nature 292:154-156, 1981; M. O. Bradley et al., Nature 309: 255-258, 1984; Gossler, et al., Proc. Natl. Acad. Sci USA 83: 9065-9069, 1986; and Robertson et al., Nature 322:445-448, 1986). Transgenes can be efficiently introduced into the ES cells by DNA transfection or by retro virus-mediated transduction. Such transformed ES cells can thereafter be combined with blastocysts from a nonhuman animal. The ES cells thereafter colonize the embryo and contribute to the germ line of the resulting chimeric animal. (For review see Jaenisch, R., Science 240: 1468-1474, 1988).

"Transformed" means a cell into which (or into an ancestor of which) has been introduced, by means of recombinant nucleic acid techniques, a heterologous nucleic acid molecule. "Heterologous" refers to a nucleic acid sequence that either originates from another species or is modified from either its original form or the form primarily expressed in the cell.

"Transgene" means any piece of DNA which is inserted by artifice into a cell, and becomes part of the genome of the organism (i.e., either stably integrated or as a stable extrachromosomal element) which develops from that cell. Such a transgene may include a gene which is partly or entirely heterologous (i.e., foreign) to the transgenic organism, or may represent a gene homologous to an endogenous gene of the organism. Included within this definition is a transgene created by the providing of an RNA sequence which is transcribed into DNA and then incorporated into the genome. The transgenes of the invention include DNA sequences which encode which encodes the fluorescent indicator which may be expressed in a transgenic non-human animal. The term "transgenic" as used herein additionally includes any organism whose genome has been altered by in vitro manipulation of the early embryo or fertilized egg or by any transgenic technology to induce a specific gene knockout. The term "gene knockout" as used herein, refers to the targeted disruption of a gene in vivo with complete loss of function that has been achieved by any transgenic technology familiar to those in the art. In one embodiment, transgenic animals having gene knockouts are those in which the target gene has been rendered nonfunctional by an insertion targeted to the gene to be rendered non-functional by homologous recombination. As used herein, the term "transgenic" includes any transgenic technology familiar to those in the art which can produce an organism carrying an introduced transgene or one in which an endogenous gene has been rendered non-functional or "knocked out."

Without further elaboration, it is believed that one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent. All patents and publications cited herein are hereby incorporated by reference.

A fluorescent indicator for Ca²⁺ was produced by sandwiching CaM-M13 fusion, described in Porumb, T., et al., Prot.Engineering 7:109-115 (1994), between a blue (P4-3) and a green (S65T) GFP mutant, as illustrated in FIG. 2a. The chimeric cDNA was cloned at BamHI/EcoRI sites of pRSETB (Invitrogen), HIS is the amino-terminal tag peptide containing the polyhistidine sequence and XCaM is Xenopus calmodulin. Chimeric proteins incorporating a polyhistidine tag were expressed in Escherichia coli, purified by nickel-chelate and size-exclusion chromatography, and their fluorescence characterized. Referring to FIG. 2a, the fluorescent CaM-based indicator ("cameleon-1") readily changes emission color by retracting and extending a long tongue (M13) into and out of the mouth of the CaM.

The amino acid composition of the boundary regions between the CaM-M13 hybrid and GFPs can be important to optimize protein folding and the Ca²⁺ -sensitivity of FRET. One particularly sensitive indicator is shown in FIG. 2b. Referring to FIG. 2b, the amino acid and nucleotide sequences of the boundaries between P4-3 and CaM and between M13 and S65T in cameleon-1 are shown. Cameleon-1 has an 11 amino acid deletion at the C-terminus of P4-3 and a 5 amino acid deletion at the C-terminus of M13. Two restriction sites SphI and SacI are underlined, which were utilized to connect the genes of P4-3 and S65T to the CaM-M13 gene, respectively. To facilitate the folding of the GFP that is fused to any other protein, a few glycine residues are usually inserted into the boundary. See, for example, Porumb, T., et al., Prot. Engineering 7:109-115 (1994). Further, glycine residues were not introduced so that P4-3 and S65T were fused rigidly to the CaM and M13, respectively. The rigid fusion leads to more effective transduction of the conformational change of CaM-M13, causing a greater change in FRET efficiency.

The fluorescent indicator was efficiently expressed and folded in bacteria and increased its ratio of UV-excited 510 nm to 445 nm emissions by 70% upon binding Ca²⁺, as shown in FIG. 3. The emission spectra of cameleon-1 were measured in 100 mM KCl, 20 mM MOPS, 1 mM EDTA, KOH to pH 7.20, before and after addition of 2 mM CaCl₂ to give 1 mM free Ca²⁺. The Ca²⁺ binding to EDTA caused a local acidification of the solution, and a small fraction of the protein was denatured. Thus the spectrum after the Ca²⁺ addition dropped down slightly (compare with FIG. 4a). The decrease in blue and increase in green emission indicated that Ca²⁺ increased the efficiency of FRET from P4-3 to S65T, consistent with the expected decrease in distance between the two ends of the protein. The Ca²⁺ response was fully reversible upon chelation of Ca²⁺.

The Ca²⁺ -specificity of the response of cameleon-1 was examined. Mg²⁺, pH, and ionic strength did not alter the emission spectra of either the Ca²⁺ -saturated and Ca²⁺ -unsaturated forms. The emission spectra of saturated and unsaturated cameleon-1 were also not affected by hydrophobic proteins such as bovine serum albumin. Isolated CaM saturated with Ca²⁺ typically becomes sticky with hydrophobic amino acids exposed to the surface. The CaM in cameleon-1, on the other hand, appears to interact preferentially with its intramolecularly-adjacent M13 peptide. The self-contained nature of the system minimizes the possibility that the protein might interact with endogenous CaM-binding sequences in eukaryotic cells.

The Ca²⁺ binding behavior of cameleon-1 was examined. The CaM-M13 hybrid protein without GFPs displayed a biphasic Ca²⁺ binding with two dissociation constants (80 nM and 2 μM). See, Porumb, T., et al., Prot.Engineering 7:109-115 (1994). Titration experiments revealed that the emission ratio of cameleon-1 has a biphasic Ca²⁺ dependency, as shown in FIGS. 4a and 4b. FIG. 4a shows the change in emission spectrum of cameleon-1 on titration with Ca²⁺ when excited at 380 nm. The titration was done using KHHEDTA/KCaHEDTA solutions at pH 7.47. For clarity only two intermediate concentrations of Ca²⁺ are shown.

FIG. 4b shows Ca²⁺ titration curves of cameleon-1 (open circles) and cameleon-1/E104Q (solid circles). Data points were from 4 independent experiments at different pH using Ca²⁺ /EGTA and Ca²⁺ /HEEDTA systems for each protein. In each experiment, the emission ratio (510/445 nm) change was normalized to the value of full saturation with Ca²⁺, which increased by 60-75% over the value of zero Ca²⁺. The data of cameleon-1/E104Q were fitted to a four parameter logistic function curve (dotted line). The data of cameleon-1 were analysed using a linear combination of 2 four parameter logistic function fits (solid line). The apparent dissociation constants (K'_(d) s) for cameleon-1 were 68 nM and 11 μM, and the Hill coefficients were 1.8 and 1.0, respectively. The binding curve can be used to quantify the concentration of Ca²⁺ present in the sample. Because of simulated negative cooperativity, cameleon-1 covers a very wide range of Ca²⁺ concentration, from <10⁻⁷ to ˜10⁻³ M.

The affinity of the CaM binding protein moiety can be modified. Many site-directed mutations have been studied for their effects on the Ca²⁺ binding and Ca²⁺ -induced conformational changes of CaM. See, Maune, J. F., et al., J.Biol.Chem. 267:5286-5295 (1992), and Gao, Z. H., et al., J.Biol.Chem. 268:20096-20104 (1993). For example, a mutant chimera protein with the conserved bidentate glutamic acid at position 12 of the third Ca²⁺ binding loop of the CaM mutated to glutamine (cameleon-1/E104Q) was constructed. The mutation eliminated the high-affinity response of cameleon-1, as indicated in FIG. 4b, (solid circles). Cameleon-1/E104Q showed a monophasic response (K'd, 4.4 μM; Hill coefficient, 0.76), which corresponds closely to the low affinity component of the cameleon-1 FRET response. Other modifications of CaM can be made to tune the Ca²⁺ affinities for particular applications of the fluorescent indicator.

HeLa cells were transfected with the recombinant plasmid (cameleon-1/pCDNA3) to determine whether cameleon-1 can work as a Ca²⁺ indicator in live cells. When the cells were excited with UV, however, the fluorescence of cameleon-1 was hardly detectable, mainly because of the dim fluorescence of the P4-3 component. Expression and folding of GFP at 37° C. in mammalian cells was improved by introducing mammalian codon bias into the cDNA and mutating Phe64 to Leu, as in the commercially available construct "EGFP" (Clonetech), which encodes F64L/S65T with mammalian codons. The same changes were introduced into P4-3 (Y66H/Y145F), which did not change its final fluorescence properties but did improve expression in the HeLa cells. The improved blue mutant ("EBFP") and EGFP substituted P4-3 and S65T, respectively, in cameleon-1 to make cameleon-2, shown in FIG. 5, where Kz is Kozak's consensus sequence (M. Kozak, J. Cell Biol. 108:229-241 (1989). The nucleotide sequence (SEQ ID NO:1) and amino acid sequence (SEQ ID NO:2) of cameleon-2 are shown in FIG. 7.

The E104Q mutation which afforded low Ca²⁺ affinity in cameleon-1 was also introduced into cameleon-2; the resulting chimera protein (cameleon-2/E104Q) cameleon-3, also shown in FIG. 5. The nucleotide sequence (SEQ ID NO:5) and amino acid sequence (SEQ ID NO:6) of cameleon-3 are shown in FIG. 9.

Significant emission signals were observed from both the EBFP and EGFP in the cells expressing cameleon-2 or cameleon-3. Referring to FIG. 6a, fluorescence of cameleon-2 localized to the cytosol of HeLa cells. The fluorescence was uniformly distributed in the cytosolic compartment but excluded from the nucleus, as expected for a protein of 74 kDa without localization sequences or targeting signals. The image was taken using a 330WB80 (excitation filter) and a 535DF45 (emission filter). The bar is 10 μm.

FIG. 6b shows time courses of the spatially averaged green:blue emission ratios from two individual HeLa cells expressing cameleon-2. The two cells shown in FIG. 6a were excited by UV (330WB80) and monitored every 15 seconds by digital imaging microscopy. See, for example, Tsien, R. Y. & Harootunian, A. T. Cell Calcium, 11:93-109 (1990). The emission bands (440DF40 and 535DF45) over the cytoplasmic regions were alternately sampled. In situ calibration was performed for each of the cells. The pre-stimulation ratio (arrowhead) was assumed to be 50 nM, and R_(max) (arrow) the value after saturation with Ca²⁺. The calculated values for pCas 7, 6, 5, 4 are indicated by horizontal bars on the right side of the panel.

Elevation of cytosolic Ca²⁺ concentration by saturating doses of ATP (as a purinergic agonist) and histamine produced significant increases in the emission ratio. Blockage of the histamine receptor by the antagonist cyproheptadine caused a rapid decrease in ratio, indicating the reversible behavior of the indicator. Addition of ionomycin followed by a high concentration (15 mM) of extracellular Ca²⁺ gave a large increase of the ratio (70-80% increase of the initial ratio value), which should correspond to the maximal ratio R_(max). Assuming the lowest ratio observed before stimulation represents the R_(min), calibration for free Ca²⁺ concentration can be performed. See, Adams, S. R., et al., in Fluorescent and Luminescent Probes for Biological Activity (ed. Mason, W. T.) (Academic Press, 1993).

By contrast, cameleon-3, which lacks the high affinity component of Ca²⁺ binding to CaM, did not detect the changes in cytosolic Ca²⁺ concentration signals due to ATP or histamine, but gave a similar R_(max) in response to ionomycin and 20 mM extracellular Ca²⁺. Cameleon-3 is less sensitive to and buffers cytosolic Ca²⁺ to a lesser extent than does cameleon-2. The probable high Ca²⁺ dissociation rate of cameleon-3 is advantageous for tracking rapid Ca²⁺ release kinetics. The in vitro study revealed that the cameleon indicators show a relatively fast cellular response to Ca²⁺ concentration changes.

Addition of a nuclear localization sequence to cameleon-2 yielded a Ca²⁺ indicator, cameleon-2nu, shown in FIG. 5. The nucleotide sequence (SEQ ID NO:3) and amino acid sequence (SEQ ID NO:4) of cameleon-2nu are shown in FIG. 8. The fluorescence of cameleon-2nu was localized to nuclei, as depicted in FIG. 6c. The time course of Ca²⁺ concentrations in nuclei was followed (FIG. 6d) and was similar to the results obtained in the cytosol (FIG. 6b).

Agonist-induced changes in the free Ca²⁺ concentration inside the endoplasmic reticulum in intact cells were similarly monitored. The low-affinity indicator cameleon-3 was engineered to reside in the lumen of endoplasmic reticulum (ER) (cameleon-3er) (FIG. 5) by addition of a localization sequence at the amino terminus and a KDEL signal for ER retention at the carboxy terminus of the fluorescent indicator. The nucleotide sequence (SEQ ID NO:7) and amino acid sequence of cameleon-3er (SEQ ID NO:8) are shown in FIG. 10. Reticular patterns of fluorescence were seen in HeLa cells expressing the protein. FIG. 6e is a digital fluorescence image of cameleon-3er in transfected HeLa cells. The image was obtained with a cooled CCD camera system with a 480DF30 (excitation filter) and a 535DF45 (emission filter). The bar is 10 μm.

FIG. 6f shows a time course of the average Ca²⁺ _(er) concentration of four cells obtained with a video-rate confocal microscope. Digital fluorescence images were the result of simultaneous acquisition of two confocal single-wavelength emission images at 450 nm (65 nm bandpass) and 535 nm (45 nm bandpass). After background subtraction, the ratio of the long wavelength image over the short wavelength one was calculated. Cells were illuminated for 66 msec (2 frames) for each time point. The interference filters and dichroics, and the sensitivity of the detectors are different between the CCD and confocal microscope systems. Therefore, the ratios obtained in the two systems differ quantitatively.

The pre-stimulus Ca²⁺ _(er) concentration reported by cameleon-3er was consistently higher than cytosolic or nuclear Ca²⁺ concentrations reported by cameleon-2 and cameleon-2nu, respectively. Histamine reproducibly decreased the Ca²⁺ _(er) concentration in all of 15 cells, whereas it always increased the cytosolic and nuclear Ca²⁺ concentrations. Receptor blockade by cyproheptadine reversed the decrease Ca²⁺ _(er) concentration, indicating refill of the Ca²⁺ pools. In FIG. 6f, the ratio did not reach the value of the resting state, whereas complete reversion was observed in five other experiments. Addition of ionomycin and 20 mM extracellular Ca²⁺ increased Ca²⁺ _(er) concentration to a saturating value above the starting level. Changes in Ca²⁺ _(er) concentration were generally slower than those of the cytosol and nuclei.

The targetability of the fluorescent indicators can permit Ca²⁺ measurements at previously inaccessible sites such as the immediate vicinity of synaptic vesicles or Ca²⁺ channels, and in genetically tractable organisms that do not load well with esters of small-molecule indicators.

The Examples described below are illustrative of the disclosed method; however, many alternatives, modifications and variations will be clear to those skilled in the art.

EXAMPLES

Gene Construction

The cDNA of the GFP mutant P4-3 was amplified by PCR with a sense primer containing a BamHI site, and a reverse primer containing an SphI site and eliminating the GFP stop codon. See, for example, Heim, R. & Tsien, R. Y. Current Biol. 6:178-182 (1996). Likewise, the cDNA of S65T was amplified with a SacI site and an EcoRI site introduced to the 5' and 3' ends of the gene, respectively. Two restriction sites (SphI and SacI) were introduced by PCR into 5' and 3' ends of the CaM-M13 gene, respectively, using the pHY1 as a template. See, Porumb, T., et al. Prot. Engineering 7:109-115 (1994). All the amplification reactions were done by Pfu polymerase (Stratagene). The restricted products were ligated and cloned in-frame into the BamHI/EcoRI sites of pRSETB (Invitrogen). The modifications of the boundary regions between P4-3 and CaM and between M13 and S65T were performed by PCR or by a combined use of restriction enzymes, Klenow fragment of DNA polymerase I, T4 DNA polymerase, mung bean exonuclease, and T4 DNA ligase as described, for example, in Molecular Cloning, A Laboratory Manual (eds. Sambrook, J., Fritsch, E. F. & Maniatis, T.) (CSH Laboratory Press, 1989). The phEGFP plasmid was commercially available from Clontech. Two amino acid substitutions (Y66H and Y145F) were made in hEGFP to construct EBFP. Oligonucleotide-directed mutageneses were carried out using the Muta-Gene Phagemid in vitro kit (Bio-Rad) at the codons for Y66H and Y145F of EGFP, and for E104Q of the calmodulin. The 5' end of the EBFP gene was modified by PCR to have a HindIII restriction site followed by a Kozak's consensus sequence (ACCGCC-ATG). The HindIII/EcoRI fragment encoding the entire chimeric protein was subcloned in the mammalian expression vector pCDNA3 (Invitrogen).

For cameleon-2nu, the cameleon-2 DNA was extended by PCR at the 3' end with the sequence encoding the nuclear localization sequence (PKKKRKVEDP) (SEQ ID NO:55). See, Forbes, D. J. Ann.Rev.Cell Biol. 8:495-527 (1992). Cameleon-3er DNA was likewise obtained by extending the cameleon-3 DNA at the 5' end with the sequence encoding the localization sequence peptide from calreticulin (MLLPVPLLLGLLGLAAAD) (SEQ ID NO:56), and at the 3' end with the sequence encoding the ER retention signal (KDEL). See, Kendall, J. M. et al., Biochem. Biophys. Res. Commun. 189:1008-1016 (1992).

Protein Expression and Spectroscopy

The expression of chimera proteins in bacteria was performed using the T7 expresson system (pRSETB/JM109(DE3)). Cultures were grown at room temperature, and protein expression was induced by isopropyl B-D-thiogalactoside. Cells were lysed by a French press. The polyhistidine-tagged chimera proteins were purified from the cleared lysates on nickel-chelate columns (Qiagen). The protein samples in the eluates were concentrated by Centricon 30 (Amicon), and were further purified by gel-filtration column to remove abortive chimera proteins which resulted from proteolysis or misfolding. Emission spectra of the purified proteins were measured using a fluorometer (Spex Industries, Edison, N.J.) at excitation 380 nm.

Ca²⁺ Titration and Calibration

The titration experiments were performed by the "pH-metric method" as described in Grzegorz, G., et al., J. Biol. Chem. 260:3440-3450 (1985). In situ calibration for cytosolic Ca²⁺ concentration utilized the equation:

    [Ca.sup.2+ ]c=K'.sub.d ((R-R.sub.min)/(R.sub.max -R)).sup.(1/nH)

where K'_(d) is the apparent dissociation constant corresponding to the Ca²⁺ concentration at which R is midway between R_(max) and R_(min), and nH is the Hill coefficient.

Imaging

Two to five days after the cDNA transfection with lipofectin (Gibco BRL), the cells were imaged on a Zeiss Axiovert microscope with a cooled CCD camera (Photometrics, Tucson, Ariz.) interfaced to a personal computer. The program MetaFluor 2.75 (Universal Imaging) was used for controlling data acquisition and analysis. Dual-emission ratio imaging was carried out by manually switching the two emission filters (440DF40 for EBFP, 535DF45 for EGFP) in front of a single imaging camera. The excitation filter (330WB80) was used with a 420DRLP dichroic mirror. Digital fluorescence imaging with a video-rate confocal microscope was performed as described in Tsien, R. Y. & Backskai, B. J. Handbook of Biological Confocal Microscopy (ed. Pawley, J. B.) (Plenum Press, New York, 1995) p. 459-478. Cells were illuminated with wide band UV (351-364 nm) from an Ar⁺ ion laser. The primary dichroic (380DRLP) reflects UV and transmits light emitted from the specimen, which is subsequently split by a secondary dichroic (505DRLP) into two broad bands: EBFP emission (450DF65) and EGFP emission (535DF45), and counted by photomultiplier tubes.

From the above description, the essential characteristics of the present invention can be ascertained. Without departing from the spirit and scope thereof, various changes and modifications of the invention can be made to adapt it to various usages and conditions. Thus, other embodiments are also within the claims.

    __________________________________________________________________________     #             SEQUENCE LISTING                                                    - -  - - (1) GENERAL INFORMATION:                                              - -    (iii) NUMBER OF SEQUENCES: 61                                           - -  - - (2) INFORMATION FOR SEQ ID NO:1:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1929 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Coding Se - #quence                                              (B) LOCATION: 1...1926                                                - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:                                - - ATG GTG AGC AAG GGC GAG GAG CTG TTC ACC GG - #G GTG GTG CCC ATC         CTG       48                                                                     Met Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu             1               5 - #                 10 - #                 15               - - GTC GAG CTG GAC GGC GAC GTA AAC GGC CAC AA - #G TTC AGC GTG TCC GGC            96                                                                        Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                         20     - #             25     - #             30                   - - GAG GGC GAG GGC GAT GCC ACC TAC GGC AAG CT - #G ACC CTG AAG TTC ATC           144                                                                        Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile                     35         - #         40         - #         45                       - - TGC ACC ACC GGC AAG CTG CCC GTG CCC TGG CC - #C ACC CTC GTG ACC ACC           192                                                                        Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr                 50             - #     55             - #     60                           - - CTG ACC CAT GGC GTG CAG TGC TTC AGC CGC TA - #C CCC GAC CAC ATG AAG           240                                                                        Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys             65                 - # 70                 - # 75                 - # 80        - - CAG CAC GAC TTC TTC AAG TCC GCC ATG CCC GA - #A GGC TAC GTC CAG GAG           288                                                                        Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                             85 - #                 90 - #                 95               - - CGC ACC ATC TTC TTC AAG GAC GAC GGC AAC TA - #C AAG ACC CGC GCC GAG           336                                                                        Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu                        100      - #           105      - #           110                   - - GTG AAG TTC GAG GGC GAC ACC CTG GTG AAC CG - #C ATC GAG CTG AAG GGC           384                                                                        Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly                    115          - #       120          - #       125                       - - ATC GAC TTC AAG GAG GAC GGC AAC ATC CTG GG - #G CAC AAG CTG GAG TAC           432                                                                        Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr                130              - #   135              - #   140                           - - AAC TTC AAC AGC CAC AAC GTC TAT ATC ATG GC - #C GAC AAG CAG AAG AAC           480                                                                        Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys Asn            145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - GGC ATC AAG GTG AAC TTC AAG ATC CGC CAC AA - #C ATC GAG GAC GGC         AGC      528                                                                     Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly Ser                           165  - #               170  - #               175               - - GTG CAG CTC GCC GAC CAC TAC CAG CAG AAC AC - #C CCC ATC GGC GAC GGC           576                                                                        Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly                        180      - #           185      - #           190                   - - CCC GTG CTG CTG CCC GAC AAC CAC TAC CTG AG - #C ACC CAG TCC GCC CTG           624                                                                        Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu                    195          - #       200          - #       205                       - - AGC AAA GAC CCC AAC GAG AAG CGC GAT CAC AT - #G GTC CTG CTG GAG TTC           672                                                                        Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe                210              - #   215              - #   220                           - - GTG ACC GCC GCC CGC ATG CAT GAC CAA CTG AC - #A GAA GAG CAG ATT GCA           720                                                                        Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile Ala            225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - GAG TTC AAA GAA GCC TTC TCA TTA TTC GAC AA - #G GAT GGG GAC GGC         ACC      768                                                                     Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly Thr                           245  - #               250  - #               255               - - ATC ACC ACA AAG GAA CTT GGC ACC GTT ATG AG - #G TCG CTT GGA CAA AAC           816                                                                        Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn                        260      - #           265      - #           270                   - - CCA ACG GAA GCA GAA TTG CAG GAT ATG ATC AA - #T GAA GTC GAT GCT GAT           864                                                                        Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp                    275          - #       280          - #       285                       - - GGC AAT GGA ACG ATT TAC TTT CCT GAA TTT CT - #T ACT ATG ATG GCT AGA           912                                                                        Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg                290              - #   295              - #   300                           - - AAA ATG AAG GAC ACA GAC AGC GAA GAG GAA AT - #C CGA GAA GCA TTC CGT           960                                                                        Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe Arg            305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - GTT TTT GAC AAG GAT GGG AAC GGC TAC ATC AG - #C GCT GCT GAA TTA         CGT     1008                                                                     Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Glu Leu Arg                           325  - #               330  - #               335               - - CAC GTC ATG ACA AAC CTC GGG GAG AAG TTA AC - #A GAT GAA GAA GTT GAT          1056                                                                        His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp                        340      - #           345      - #           350                   - - GAA ATG ATA AGG GAA GCA GAT ATC GAT GGT GA - #T GGC CAA GTA AAC TAT          1104                                                                        Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr                    355          - #       360          - #       365                       - - GAA GAG TTT GTA CAA ATG ATG ACA GCA AAG GG - #G GGG AAG AGG CGC TGG          1152                                                                        Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp                370              - #   375              - #   380                           - - AAG AAA AAC TTC ATT GCC GTC AGC GCT GCC AA - #C CGG TTC AAG AAG ATC          1200                                                                        Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys Ile            385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - TCC GAG CTC ATG GTG AGC AAG GGC GAG GAG CT - #G TTC ACC GGG GTG         GTG     1248                                                                     Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val Val                           405  - #               410  - #               415               - - CCC ATC CTG GTC GAG CTG GAC GGC GAC GTA AA - #C GGC CAC AAG TTC AGC          1296                                                                        Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser                        420      - #           425      - #           430                   - - GTG TCC GGC GAG GGC GAG GGC GAT GCC ACC TA - #C GGC AAG CTG ACC CTG          1344                                                                        Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu                    435          - #       440          - #       445                       - - AAG TTC ATC TGC ACC ACC GGC AAG CTG CCC GT - #G CCC TGG CCC ACC CTC          1392                                                                        Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu                450              - #   455              - #   460                           - - GTG ACC ACC CTG ACC TAC GGC GTG CAG TGC TT - #C AGC CGC TAC CCC GAC          1440                                                                        Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro Asp            465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - CAC ATG AAG CAG CAC GAC TTC TTC AAG TCC GC - #C ATG CCC GAA GGC         TAC     1488                                                                     His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly Tyr                           485  - #               490  - #               495               - - GTC CAG GAG CGC ACC ATC TTC TTC AAG GAC GA - #C GGC AAC TAC AAG ACC          1536                                                                        Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr                        500      - #           505      - #           510                   - - CGC GCC GAG GTG AAG TTC GAG GGC GAC ACC CT - #G GTG AAC CGC ATC GAG          1584                                                                        Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu                    515          - #       520          - #       525                       - - CTG AAG GGC ATC GAC TTC AAG GAG GAC GGC AA - #C ATC CTG GGG CAC AAG          1632                                                                        Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys                530              - #   535              - #   540                           - - CTG GAG TAC AAC TAC AAC AGC CAC AAC GTC TA - #T ATC ATG GCC GAC AAG          1680                                                                        Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp Lys            545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - CAG AAG AAC GGC ATC AAG GTG AAC TTC AAG AT - #C CGC CAC AAC ATC         GAG     1728                                                                     Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile Glu                           565  - #               570  - #               575               - - GAC GGC AGC GTG CAG CTC GCC GAC CAC TAC CA - #G CAG AAC ACC CCC ATC          1776                                                                        Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile                        580      - #           585      - #           590                   - - GGC GAC GGC CCC GTG CTG CTG CCC GAC AAC CA - #C TAC CTG AGC ACC CAG          1824                                                                        Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln                    595          - #       600          - #       605                       - - TCC GCC CTG AGC AAA GAC CCC AAC GAG AAG CG - #C GAT CAC ATG GTC CTG          1872                                                                        Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu                610              - #   615              - #   620                           - - CTG GAG TTC GTG ACC GCC GCC GGG ATC ACT CT - #C GGC ATG GAC GAG CTG          1920                                                                        Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Met Asp Glu Leu            625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - TAC AAG TAA              - #                  - #                       - #       1929                                                                  Tyr Lys                                                                         - -  - - (2) INFORMATION FOR SEQ ID NO:2:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 642 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -      (v) FRAGMENT TYPE: internal                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:                                - - Met Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu         1               5 - #                 10 - #                 15               - - Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                    20     - #             25     - #             30                   - - Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile                35         - #         40         - #         45                       - - Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr            50             - #     55             - #     60                           - - Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys        65                 - # 70                 - # 75                 - # 80        - - Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                        85 - #                 90 - #                 95               - - Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu                   100      - #           105      - #           110                   - - Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly               115          - #       120          - #       125                       - - Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr           130              - #   135              - #   140                           - - Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys Asn       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly         Ser                                                                                              165  - #               170  - #               175              - - Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly                   180      - #           185      - #           190                   - - Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu               195          - #       200          - #       205                       - - Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe           210              - #   215              - #   220                           - - Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile Ala       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly         Thr                                                                                              245  - #               250  - #               255              - - Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn                   260      - #           265      - #           270                   - - Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp               275          - #       280          - #       285                       - - Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg           290              - #   295              - #   300                           - - Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe Arg       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Glu Leu         Arg                                                                                              325  - #               330  - #               335              - - His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp                   340      - #           345      - #           350                   - - Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr               355          - #       360          - #       365                       - - Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp           370              - #   375              - #   380                           - - Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys Ile       385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val         Val                                                                                              405  - #               410  - #               415              - - Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser                   420      - #           425      - #           430                   - - Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu               435          - #       440          - #       445                       - - Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu           450              - #   455              - #   460                           - - Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro Asp       465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly         Tyr                                                                                              485  - #               490  - #               495              - - Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr                   500      - #           505      - #           510                   - - Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu               515          - #       520          - #       525                       - - Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys           530              - #   535              - #   540                           - - Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp Lys       545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile         Glu                                                                                              565  - #               570  - #               575              - - Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile                   580      - #           585      - #           590                   - - Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln               595          - #       600          - #       605                       - - Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu           610              - #   615              - #   620                           - - Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Met Asp Glu Leu       625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - Tyr Lys                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:3:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1959 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Coding Se - #quence                                              (B) LOCATION: 1...1956                                                - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:                                - - ATG GTG AGC AAG GGC GAG GAG CTG TTC ACC GG - #G GTG GTG CCC ATC         CTG      48                                                                      Met Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu             1               5 - #                 10 - #                 15               - - GTC GAG CTG GAC GGC GAC GTA AAC GGC CAC AA - #G TTC AGC GTG TCC GGC           96                                                                         Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                         20     - #             25     - #             30                   - - GAG GGC GAG GGC GAT GCC ACC TAC GGC AAG CT - #G ACC CTG AAG TTC ATC          144                                                                         Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile                     35         - #         40         - #         45                       - - TGC ACC ACC GGC AAG CTG CCC GTG CCC TGG CC - #C ACC CTC GTG ACC ACC          192                                                                         Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr                 50             - #     55             - #     60                           - - CTG ACC CAT GGC GTG CAG TGC TTC AGC CGC TA - #C CCC GAC CAC ATG AAG          240                                                                         Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys             65                 - # 70                 - # 75                 - # 80        - - CAG CAC GAC TTC TTC AAG TCC GCC ATG CCC GA - #A GGC TAC GTC CAG GAG          288                                                                         Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                             85 - #                 90 - #                 95               - - CGC ACC ATC TTC TTC AAG GAC GAC GGC AAC TA - #C AAG ACC CGC GCC GAG          336                                                                         Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu                        100      - #           105      - #           110                   - - GTG AAG TTC GAG GGC GAC ACC CTG GTG AAC CG - #C ATC GAG CTG AAG GGC          384                                                                         Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly                    115          - #       120          - #       125                       - - ATC GAC TTC AAG GAG GAC GGC AAC ATC CTG GG - #G CAC AAG CTG GAG TAC          432                                                                         Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr                130              - #   135              - #   140                           - - AAC TTC AAC AGC CAC AAC GTC TAT ATC ATG GC - #C GAC AAG CAG AAG AAC          480                                                                         Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys Asn            145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - GGC ATC AAG GTG AAC TTC AAG ATC CGC CAC AA - #C ATC GAG GAC GGC         AGC     528                                                                      Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly Ser                           165  - #               170  - #               175               - - GTG CAG CTC GCC GAC CAC TAC CAG CAG AAC AC - #C CCC ATC GGC GAC GGC          576                                                                         Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly                        180      - #           185      - #           190                   - - CCC GTG CTG CTG CCC GAC AAC CAC TAC CTG AG - #C ACC CAG TCC GCC CTG          624                                                                         Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu                    195          - #       200          - #       205                       - - AGC AAA GAC CCC AAC GAG AAG CGC GAT CAC AT - #G GTC CTG CTG GAG TTC          672                                                                         Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe                210              - #   215              - #   220                           - - GTG ACC GCC GCC CGC ATG CAT GAC CAA CTG AC - #A GAA GAG CAG ATT GCA          720                                                                         Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile Ala            225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - GAG TTC AAA GAA GCC TTC TCA TTA TTC GAC AA - #G GAT GGG GAC GGC         ACC     768                                                                      Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly Thr                           245  - #               250  - #               255               - - ATC ACC ACA AAG GAA CTT GGC ACC GTT ATG AG - #G TCG CTT GGA CAA AAC          816                                                                         Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn                        260      - #           265      - #           270                   - - CCA ACG GAA GCA GAA TTG CAG GAT ATG ATC AA - #T GAA GTC GAT GCT GAT          864                                                                         Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp                    275          - #       280          - #       285                       - - GGC AAT GGA ACG ATT TAC TTT CCT GAA TTT CT - #T ACT ATG ATG GCT AGA          912                                                                         Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg                290              - #   295              - #   300                           - - AAA ATG AAG GAC ACA GAC AGC GAA GAG GAA AT - #C CGA GAA GCA TTC CGT          960                                                                         Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe Arg            305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - GTT TTT GAC AAG GAT GGG AAC GGC TAC ATC AG - #C GCT GCT GAA TTA         CGT    1008                                                                      Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Glu Leu Arg                           325  - #               330  - #               335               - - CAC GTC ATG ACA AAC CTC GGG GAG AAG TTA AC - #A GAT GAA GAA GTT GAT         1056                                                                         His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp                        340      - #           345      - #           350                   - - GAA ATG ATA AGG GAA GCA GAT ATC GAT GGT GA - #T GGC CAA GTA AAC TAT         1104                                                                         Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr                    355          - #       360          - #       365                       - - GAA GAG TTT GTA CAA ATG ATG ACA GCA AAG GG - #G GGG AAG AGG CGC TGG         1152                                                                         Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp                370              - #   375              - #   380                           - - AAG AAA AAC TTC ATT GCC GTC AGC GCT GCC AA - #C CGG TTC AAG AAG ATC         1200                                                                         Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys Ile            385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - TCC GAG CTC ATG GTG AGC AAG GGC GAG GAG CT - #G TTC ACC GGG GTG         GTG    1248                                                                      Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val Val                           405  - #               410  - #               415               - - CCC ATC CTG GTC GAG CTG GAC GGC GAC GTA AA - #C GGC CAC AAG TTC AGC         1296                                                                         Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser                        420      - #           425      - #           430                   - - GTG TCC GGC GAG GGC GAG GGC GAT GCC ACC TA - #C GGC AAG CTG ACC CTG         1344                                                                         Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu                    435          - #       440          - #       445                       - - AAG TTC ATC TGC ACC ACC GGC AAG CTG CCC GT - #G CCC TGG CCC ACC CTC         1392                                                                         Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu                450              - #   455              - #   460                           - - GTG ACC ACC CTG ACC TAC GGC GTG CAG TGC TT - #C AGC CGC TAC CCC GAC         1440                                                                         Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro Asp            465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - CAC ATG AAG CAG CAC GAC TTC TTC AAG TCC GC - #C ATG CCC GAA GGC         TAC    1488                                                                      His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly Tyr                           485  - #               490  - #               495               - - GTC CAG GAG CGC ACC ATC TTC TTC AAG GAC GA - #C GGC AAC TAC AAG ACC         1536                                                                         Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr                        500      - #           505      - #           510                   - - CGC GCC GAG GTG AAG TTC GAG GGC GAC ACC CT - #G GTG AAC CGC ATC GAG         1584                                                                         Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu                    515          - #       520          - #       525                       - - CTG AAG GGC ATC GAC TTC AAG GAG GAC GGC AA - #C ATC CTG GGG CAC AAG         1632                                                                         Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys                530              - #   535              - #   540                           - - CTG GAG TAC AAC TAC AAC AGC CAC AAC GTC TA - #T ATC ATG GCC GAC AAG         1680                                                                         Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp Lys            545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - CAG AAG AAC GGC ATC AAG GTG AAC TTC AAG AT - #C CGC CAC AAC ATC         GAG    1728                                                                      Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile Glu                           565  - #               570  - #               575               - - GAC GGC AGC GTG CAG CTC GCC GAC CAC TAC CA - #G CAG AAC ACC CCC ATC         1776                                                                         Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile                        580      - #           585      - #           590                   - - GGC GAC GGC CCC GTG CTG CTG CCC GAC AAC CA - #C TAC CTG AGC ACC CAG         1824                                                                         Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln                    595          - #       600          - #       605                       - - TCC GCC CTG AGC AAA GAC CCC AAC GAG AAG CG - #C GAT CAC ATG GTC CTG         1872                                                                         Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu                610              - #   615              - #   620                           - - CTG GAG TTC GTG ACC GCC GCC GGG ATC ACT CT - #C GGC ATG GAC GAG CTG         1920                                                                         Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Met Asp Glu Leu            625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - TAC AAG CCA AAA AAG AAG AGA AAG GTG GAA GA - #C GCT TAA                   - #  1959                                                                     Tyr Lys Pro Lys Lys Lys Arg Lys Val Glu As - #p Ala                                            645  - #               650                                      - -  - - (2) INFORMATION FOR SEQ ID NO:4:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 652 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -      (v) FRAGMENT TYPE: internal                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:                                - - Met Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu         1               5 - #                 10 - #                 15               - - Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                    20     - #             25     - #             30                   - - Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile                35         - #         40         - #         45                       - - Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr            50             - #     55             - #     60                           - - Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys        65                 - # 70                 - # 75                 - # 80        - - Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                        85 - #                 90 - #                 95               - - Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu                   100      - #           105      - #           110                   - - Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly               115          - #       120          - #       125                       - - Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr           130              - #   135              - #   140                           - - Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys Asn       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly         Ser                                                                                              165  - #               170  - #               175              - - Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly                   180      - #           185      - #           190                   - - Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu               195          - #       200          - #       205                       - - Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe           210              - #   215              - #   220                           - - Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile Ala       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly         Thr                                                                                              245  - #               250  - #               255              - - Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn                   260      - #           265      - #           270                   - - Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp               275          - #       280          - #       285                       - - Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg           290              - #   295              - #   300                           - - Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe Arg       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Glu Leu         Arg                                                                                              325  - #               330  - #               335              - - His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp                   340      - #           345      - #           350                   - - Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr               355          - #       360          - #       365                       - - Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp           370              - #   375              - #   380                           - - Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys Ile       385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val         Val                                                                                              405  - #               410  - #               415              - - Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser                   420      - #           425      - #           430                   - - Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu               435          - #       440          - #       445                       - - Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu           450              - #   455              - #   460                           - - Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro Asp       465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly         Tyr                                                                                              485  - #               490  - #               495              - - Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr                   500      - #           505      - #           510                   - - Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu               515          - #       520          - #       525                       - - Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys           530              - #   535              - #   540                           - - Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp Lys       545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile         Glu                                                                                              565  - #               570  - #               575              - - Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile                   580      - #           585      - #           590                   - - Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln               595          - #       600          - #       605                       - - Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu           610              - #   615              - #   620                           - - Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Met Asp Glu Leu       625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - Tyr Lys Pro Lys Lys Lys Arg Lys Val Glu As - #p Ala                                       645  - #               650                                      - -  - - (2) INFORMATION FOR SEQ ID NO:5:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1929 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Coding Se - #quence                                              (B) LOCATION: 1...1926                                                - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:                                - - ATG GTG AGC AAG GGC GAG GAG CTG TTC ACC GG - #G GTG GTG CCC ATC         CTG      48                                                                      Met Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu             1               5 - #                 10 - #                 15               - - GTC GAG CTG GAC GGC GAC GTA AAC GGC CAC AA - #G TTC AGC GTG TCC GGC           96                                                                         Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                         20     - #             25     - #             30                   - - GAG GGC GAG GGC GAT GCC ACC TAC GGC AAG CT - #G ACC CTG AAG TTC ATC          144                                                                         Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile                     35         - #         40         - #         45                       - - TGC ACC ACC GGC AAG CTG CCC GTG CCC TGG CC - #C ACC CTC GTG ACC ACC          192                                                                         Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr                 50             - #     55             - #     60                           - - CTG ACC CAT GGC GTG CAG TGC TTC AGC CGC TA - #C CCC GAC CAC ATG AAG          240                                                                         Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys             65                 - # 70                 - # 75                 - # 80        - - CAG CAC GAC TTC TTC AAG TCC GCC ATG CCC GA - #A GGC TAC GTC CAG GAG          288                                                                         Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                             85 - #                 90 - #                 95               - - CGC ACC ATC TTC TTC AAG GAC GAC GGC AAC TA - #C AAG ACC CGC GCC GAG          336                                                                         Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu                        100      - #           105      - #           110                   - - GTG AAG TTC GAG GGC GAC ACC CTG GTG AAC CG - #C ATC GAG CTG AAG GGC          384                                                                         Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly                    115          - #       120          - #       125                       - - ATC GAC TTC AAG GAG GAC GGC AAC ATC CTG GG - #G CAC AAG CTG GAG TAC          432                                                                         Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr                130              - #   135              - #   140                           - - AAC TTC AAC AGC CAC AAC GTC TAT ATC ATG GC - #C GAC AAG CAG AAG AAC          480                                                                         Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys Asn            145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - GGC ATC AAG GTG AAC TTC AAG ATC CGC CAC AA - #C ATC GAG GAC GGC         AGC     528                                                                      Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly Ser                           165  - #               170  - #               175               - - GTG CAG CTC GCC GAC CAC TAC CAG CAG AAC AC - #C CCC ATC GGC GAC GGC          576                                                                         Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly                        180      - #           185      - #           190                   - - CCC GTG CTG CTG CCC GAC AAC CAC TAC CTG AG - #C ACC CAG TCC GCC CTG          624                                                                         Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu                    195          - #       200          - #       205                       - - AGC AAA GAC CCC AAC GAG AAG CGC GAT CAC AT - #G GTC CTG CTG GAG TTC          672                                                                         Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe                210              - #   215              - #   220                           - - GTG ACC GCC GCC CGC ATG CAT GAC CAA CTG AC - #A GAA GAG CAG ATT GCA          720                                                                         Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile Ala            225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - GAG TTC AAA GAA GCC TTC TCA TTA TTC GAC AA - #G GAT GGG GAC GGC         ACC     768                                                                      Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly Thr                           245  - #               250  - #               255               - - ATC ACC ACA AAG GAA CTT GGC ACC GTT ATG AG - #G TCG CTT GGA CAA AAC          816                                                                         Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn                        260      - #           265      - #           270                   - - CCA ACG GAA GCA GAA TTG CAG GAT ATG ATC AA - #T GAA GTC GAT GCT GAT          864                                                                         Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp                    275          - #       280          - #       285                       - - GGC AAT GGA ACG ATT TAC TTT CCT GAA TTT CT - #T ACT ATG ATG GCT AGA          912                                                                         Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg                290              - #   295              - #   300                           - - AAA ATG AAG GAC ACA GAC AGC GAA GAG GAA AT - #C CGA GAA GCA TTC CGT          960                                                                         Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe Arg            305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - GTT TTT GAC AAG GAT GGG AAC GGC TAC ATC AG - #C GCT GCT CAG TTA         CGT    1008                                                                      Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Gln Leu Arg                           325  - #               330  - #               335               - - CAC GTC ATG ACA AAC CTC GGG GAG AAG TTA AC - #A GAT GAA GAA GTT GAT         1056                                                                         His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp                        340      - #           345      - #           350                   - - GAA ATG ATA AGG GAA GCA GAT ATC GAT GGT GA - #T GGC CAA GTA AAC TAT         1104                                                                         Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr                    355          - #       360          - #       365                       - - GAA GAG TTT GTA CAA ATG ATG ACA GCA AAG GG - #G GGG AAG AGG CGC TGG         1152                                                                         Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp                370              - #   375              - #   380                           - - AAG AAA AAC TTC ATT GCC GTC AGC GCT GCC AA - #C CGG TTC AAG AAG ATC         1200                                                                         Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys Ile            385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - TCC GAG CTC ATG GTG AGC AAG GGC GAG GAG CT - #G TTC ACC GGG GTG         GTG    1248                                                                      Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val Val                           405  - #               410  - #               415               - - CCC ATC CTG GTC GAG CTG GAC GGC GAC GTA AA - #C GGC CAC AAG TTC AGC         1296                                                                         Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser                        420      - #           425      - #           430                   - - GTG TCC GGC GAG GGC GAG GGC GAT GCC ACC TA - #C GGC AAG CTG ACC CTG         1344                                                                         Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu                    435          - #       440          - #       445                       - - AAG TTC ATC TGC ACC ACC GGC AAG CTG CCC GT - #G CCC TGG CCC ACC CTC         1392                                                                         Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu                450              - #   455              - #   460                           - - GTG ACC ACC CTG ACC TAC GGC GTG CAG TGC TT - #C AGC CGC TAC CCC GAC         1440                                                                         Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro Asp            465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - CAC ATG AAG CAG CAC GAC TTC TTC AAG TCC GC - #C ATG CCC GAA GGC         TAC    1488                                                                      His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly Tyr                           485  - #               490  - #               495               - - GTC CAG GAG CGC ACC ATC TTC TTC AAG GAC GA - #C GGC AAC TAC AAG ACC         1536                                                                         Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr                        500      - #           505      - #           510                   - - CGC GCC GAG GTG AAG TTC GAG GGC GAC ACC CT - #G GTG AAC CGC ATC GAG         1584                                                                         Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu                    515          - #       520          - #       525                       - - CTG AAG GGC ATC GAC TTC AAG GAG GAC GGC AA - #C ATC CTG GGG CAC AAG         1632                                                                         Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys                530              - #   535              - #   540                           - - CTG GAG TAC AAC TAC AAC AGC CAC AAC GTC TA - #T ATC ATG GCC GAC AAG         1680                                                                         Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp Lys            545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - CAG AAG AAC GGC ATC AAG GTG AAC TTC AAG AT - #C CGC CAC AAC ATC         GAG    1728                                                                      Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile Glu                           565  - #               570  - #               575               - - GAC GGC AGC GTG CAG CTC GCC GAC CAC TAC CA - #G CAG AAC ACC CCC ATC         1776                                                                         Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile                        580      - #           585      - #           590                   - - GGC GAC GGC CCC GTG CTG CTG CCC GAC AAC CA - #C TAC CTG AGC ACC CAG         1824                                                                         Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln                    595          - #       600          - #       605                       - - TCC GCC CTG AGC AAA GAC CCC AAC GAG AAG CG - #C GAT CAC ATG GTC CTG         1872                                                                         Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu                610              - #   615              - #   620                           - - CTG GAG TTC GTG ACC GCC GCC GGG ATC ACT CT - #C GGC ATG GAC GAG CTG         1920                                                                         Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Met Asp Glu Leu            625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - TAC AAG TAA              - #                  - #                       - #      1929                                                                   Tyr Lys                                                                         - -  - - (2) INFORMATION FOR SEQ ID NO:6:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 642 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -      (v) FRAGMENT TYPE: internal                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:                                - - Met Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu         1               5 - #                 10 - #                 15               - - Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                    20     - #             25     - #             30                   - - Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile                35         - #         40         - #         45                       - - Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr            50             - #     55             - #     60                           - - Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys        65                 - # 70                 - # 75                 - # 80        - - Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                        85 - #                 90 - #                 95               - - Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu                   100      - #           105      - #           110                   - - Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly               115          - #       120          - #       125                       - - Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr           130              - #   135              - #   140                           - - Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys Asn       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly         Ser                                                                                              165  - #               170  - #               175              - - Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly                   180      - #           185      - #           190                   - - Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu               195          - #       200          - #       205                       - - Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe           210              - #   215              - #   220                           - - Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile Ala       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly         Thr                                                                                              245  - #               250  - #               255              - - Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn                   260      - #           265      - #           270                   - - Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp               275          - #       280          - #       285                       - - Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg           290              - #   295              - #   300                           - - Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe Arg       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Gln Leu         Arg                                                                                              325  - #               330  - #               335              - - His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp                   340      - #           345      - #           350                   - - Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr               355          - #       360          - #       365                       - - Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp           370              - #   375              - #   380                           - - Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys Ile       385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val         Val                                                                                              405  - #               410  - #               415              - - Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser                   420      - #           425      - #           430                   - - Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu               435          - #       440          - #       445                       - - Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu           450              - #   455              - #   460                           - - Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro Asp       465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly         Tyr                                                                                              485  - #               490  - #               495              - - Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr                   500      - #           505      - #           510                   - - Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu               515          - #       520          - #       525                       - - Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys           530              - #   535              - #   540                           - - Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp Lys       545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile         Glu                                                                                              565  - #               570  - #               575              - - Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile                   580      - #           585      - #           590                   - - Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln               595          - #       600          - #       605                       - - Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu           610              - #   615              - #   620                           - - Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Met Asp Glu Leu       625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - Tyr Lys                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:7:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1971 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: cDNA                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Coding Se - #quence                                              (B) LOCATION: 1...1968                                                - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:                                - - ATG CTG CTG CCC GTC CCC CTG CTG CTG GGC CT - #G CTG GGC GCC GCC         GCC      48                                                                      Met Leu Leu Pro Val Pro Leu Leu Leu Gly Le - #u Leu Gly Ala Ala Ala             1               5 - #                 10 - #                 15               - - GAC GTG AGC AAG GGC GAG GAG CTG TTC ACC GG - #G GTG GTG CCC ATC CTG           96                                                                         Asp Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu                         20     - #             25     - #             30                   - - GTC GAG CTG GAC GGC GAC GTA AAC GGC CAC AA - #G TTC AGC GTG TCC GGC          144                                                                         Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                     35         - #         40         - #         45                       - - GAG GGC GAG GGC GAT GCC ACC TAC GGC AAG CT - #G ACC CTG AAG TTC ATC          192                                                                         Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile                 50             - #     55             - #     60                           - - TGC ACC ACC GGC AAG CTG CCC GTG CCC TGG CC - #C ACC CTC GTG ACC ACC          240                                                                         Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr             65                 - # 70                 - # 75                 - # 80        - - CTG ACC CAT GGC GTG CAG TGC TTC AGC CGC TA - #C CCC GAC CAC ATG AAG          288                                                                         Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys                             85 - #                 90 - #                 95               - - CAG CAC GAC TTC TTC AAG TCC GCC ATG CCC GA - #A GGC TAC GTC CAG GAG          336                                                                         Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                        100      - #           105      - #           110                   - - CGC ACC ATC TTC TTC AAG GAC GAC GGC AAC TA - #C AAG ACC CGC GCC GAG          384                                                                         Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu                    115          - #       120          - #       125                       - - GTG AAG TTC GAG GGC GAC ACC CTG GTG AAC CG - #C ATC GAG CTG AAG GGC          432                                                                         Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly                130              - #   135              - #   140                           - - ATC GAC TTC AAG GAG GAC GGC AAC ATC CTG GG - #G CAC AAG CTG GAG TAC          480                                                                         Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr            145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - AAC TTC AAC AGC CAC AAC GTC TAT ATC ATG GC - #C GAC AAG CAG AAG         AAC     528                                                                      Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys Asn                           165  - #               170  - #               175               - - GGC ATC AAG GTG AAC TTC AAG ATC CGC CAC AA - #C ATC GAG GAC GGC AGC          576                                                                         Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly Ser                        180      - #           185      - #           190                   - - GTG CAG CTC GCC GAC CAC TAC CAG CAG AAC AC - #C CCC ATC GGC GAC GGC          624                                                                         Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly                    195          - #       200          - #       205                       - - CCC GTG CTG CTG CCC GAC AAC CAC TAC CTG AG - #C ACC CAG TCC GCC CTG          672                                                                         Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu                210              - #   215              - #   220                           - - AGC AAA GAC CCC AAC GAG AAG CGC GAT CAC AT - #G GTC CTG CTG GAG TTC          720                                                                         Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe            225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - GTG ACC GCC GCC CGC ATG CAT GAC CAA CTG AC - #A GAA GAG CAG ATT         GCA     768                                                                      Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile Ala                           245  - #               250  - #               255               - - GAG TTC AAA GAA GCC TTC TCA TTA TTC GAC AA - #G GAT GGG GAC GGC ACC          816                                                                         Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly Thr                        260      - #           265      - #           270                   - - ATC ACC ACA AAG GAA CTT GGC ACC GTT ATG AG - #G TCG CTT GGA CAA AAC          864                                                                         Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn                    275          - #       280          - #       285                       - - CCA ACG GAA GCA GAA TTG CAG GAT ATG ATC AA - #T GAA GTC GAT GCT GAT          912                                                                         Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp                290              - #   295              - #   300                           - - GGC AAT GGA ACG ATT TAC TTT CCT GAA TTT CT - #T ACT ATG ATG GCT AGA          960                                                                         Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg            305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - AAA ATG AAG GAC ACA GAC AGC GAA GAG GAA AT - #C CGA GAA GCA TTC         CGT    1008                                                                      Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe Arg                           325  - #               330  - #               335               - - GTT TTT GAC AAG GAT GGG AAC GGC TAC ATC AG - #C GCT GCT CAG TTA CGT         1056                                                                         Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Gln Leu Arg                        340      - #           345      - #           350                   - - CAC GTC ATG ACA AAC CTC GGG GAG AAG TTA AC - #A GAT GAA GAA GTT GAT         1104                                                                         His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp                    355          - #       360          - #       365                       - - GAA ATG ATA AGG GAA GCA GAT ATC GAT GGT GA - #T GGC CAA GTA AAC TAT         1152                                                                         Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr                370              - #   375              - #   380                           - - GAA GAG TTT GTA CAA ATG ATG ACA GCA AAG GG - #G GGG AAG AGG CGC TGG         1200                                                                         Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp            385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - AAG AAA AAC TTC ATT GCC GTC AGC GCT GCC AA - #C CGG TTC AAG AAG         ATC    1248                                                                      Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys Ile                           405  - #               410  - #               415               - - TCC GAG CTC ATG GTG AGC AAG GGC GAG GAG CT - #G TTC ACC GGG GTG GTG         1296                                                                         Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val Val                        420      - #           425      - #           430                   - - CCC ATC CTG GTC GAG CTG GAC GGC GAC GTA AA - #C GGC CAC AAG TTC AGC         1344                                                                         Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser                    435          - #       440          - #       445                       - - GTG TCC GGC GAG GGC GAG GGC GAT GCC ACC TA - #C GGC AAG CTG ACC CTG         1392                                                                         Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu                450              - #   455              - #   460                           - - AAG TTC ATC TGC ACC ACC GGC AAG CTG CCC GT - #G CCC TGG CCC ACC CTC         1440                                                                         Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu            465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - GTG ACC ACC CTG ACC TAC GGC GTG CAG TGC TT - #C AGC CGC TAC CCC         GAC    1488                                                                      Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro Asp                           485  - #               490  - #               495               - - CAC ATG AAG CAG CAC GAC TTC TTC AAG TCC GC - #C ATG CCC GAA GGC TAC         1536                                                                         His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly Tyr                        500      - #           505      - #           510                   - - GTC CAG GAG CGC ACC ATC TTC TTC AAG GAC GA - #C GGC AAC TAC AAG ACC         1584                                                                         Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr                    515          - #       520          - #       525                       - - CGC GCC GAG GTG AAG TTC GAG GGC GAC ACC CT - #G GTG AAC CGC ATC GAG         1632                                                                         Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu                530              - #   535              - #   540                           - - CTG AAG GGC ATC GAC TTC AAG GAG GAC GGC AA - #C ATC CTG GGG CAC AAG         1680                                                                         Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys            545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - CTG GAG TAC AAC TAC AAC AGC CAC AAC GTC TA - #T ATC ATG GCC GAC         AAG    1728                                                                      Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp Lys                           565  - #               570  - #               575               - - CAG AAG AAC GGC ATC AAG GTG AAC TTC AAG AT - #C CGC CAC AAC ATC GAG         1776                                                                         Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile Glu                        580      - #           585      - #           590                   - - GAC GGC AGC GTG CAG CTC GCC GAC CAC TAC CA - #G CAG AAC ACC CCC ATC         1824                                                                         Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile                    595          - #       600          - #       605                       - - GGC GAC GGC CCC GTG CTG CTG CCC GAC AAC CA - #C TAC CTG AGC ACC CAG         1872                                                                         Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln                610              - #   615              - #   620                           - - TCC GCC CTG AGC AAA GAC CCC AAC GAG AAG CG - #C GAT CAC ATG GTC CTG         1920                                                                         Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu            625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - CTG GAG TTC GTG ACC GCC GCC GGG ATC ACT CT - #C GGC AAG GAC GAG         CTG    1968                                                                      Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Lys Asp Glu Leu                           645  - #               650  - #               655               - - TAA                  - #                  - #                  - #               1971                                                                     - -  - - (2) INFORMATION FOR SEQ ID NO:8:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 656 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -      (v) FRAGMENT TYPE: internal                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:                                - - Met Leu Leu Pro Val Pro Leu Leu Leu Gly Le - #u Leu Gly Ala Ala Ala         1               5 - #                 10 - #                 15               - - Asp Val Ser Lys Gly Glu Glu Leu Phe Thr Gl - #y Val Val Pro Ile Leu                    20     - #             25     - #             30                   - - Val Glu Leu Asp Gly Asp Val Asn Gly His Ly - #s Phe Ser Val Ser Gly                35         - #         40         - #         45                       - - Glu Gly Glu Gly Asp Ala Thr Tyr Gly Lys Le - #u Thr Leu Lys Phe Ile            50             - #     55             - #     60                           - - Cys Thr Thr Gly Lys Leu Pro Val Pro Trp Pr - #o Thr Leu Val Thr Thr        65                 - # 70                 - # 75                 - # 80        - - Leu Thr His Gly Val Gln Cys Phe Ser Arg Ty - #r Pro Asp His Met Lys                        85 - #                 90 - #                 95               - - Gln His Asp Phe Phe Lys Ser Ala Met Pro Gl - #u Gly Tyr Val Gln Glu                   100      - #           105      - #           110                   - - Arg Thr Ile Phe Phe Lys Asp Asp Gly Asn Ty - #r Lys Thr Arg Ala Glu               115          - #       120          - #       125                       - - Val Lys Phe Glu Gly Asp Thr Leu Val Asn Ar - #g Ile Glu Leu Lys Gly           130              - #   135              - #   140                           - - Ile Asp Phe Lys Glu Asp Gly Asn Ile Leu Gl - #y His Lys Leu Glu Tyr       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Asn Phe Asn Ser His Asn Val Tyr Ile Met Al - #a Asp Lys Gln Lys         Asn                                                                                              165  - #               170  - #               175              - - Gly Ile Lys Val Asn Phe Lys Ile Arg His As - #n Ile Glu Asp Gly Ser                   180      - #           185      - #           190                   - - Val Gln Leu Ala Asp His Tyr Gln Gln Asn Th - #r Pro Ile Gly Asp Gly               195          - #       200          - #       205                       - - Pro Val Leu Leu Pro Asp Asn His Tyr Leu Se - #r Thr Gln Ser Ala Leu           210              - #   215              - #   220                           - - Ser Lys Asp Pro Asn Glu Lys Arg Asp His Me - #t Val Leu Leu Glu Phe       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Val Thr Ala Ala Arg Met His Asp Gln Leu Th - #r Glu Glu Gln Ile         Ala                                                                                              245  - #               250  - #               255              - - Glu Phe Lys Glu Ala Phe Ser Leu Phe Asp Ly - #s Asp Gly Asp Gly Thr                   260      - #           265      - #           270                   - - Ile Thr Thr Lys Glu Leu Gly Thr Val Met Ar - #g Ser Leu Gly Gln Asn               275          - #       280          - #       285                       - - Pro Thr Glu Ala Glu Leu Gln Asp Met Ile As - #n Glu Val Asp Ala Asp           290              - #   295              - #   300                           - - Gly Asn Gly Thr Ile Tyr Phe Pro Glu Phe Le - #u Thr Met Met Ala Arg       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Lys Met Lys Asp Thr Asp Ser Glu Glu Glu Il - #e Arg Glu Ala Phe         Arg                                                                                              325  - #               330  - #               335              - - Val Phe Asp Lys Asp Gly Asn Gly Tyr Ile Se - #r Ala Ala Gln Leu Arg                   340      - #           345      - #           350                   - - His Val Met Thr Asn Leu Gly Glu Lys Leu Th - #r Asp Glu Glu Val Asp               355          - #       360          - #       365                       - - Glu Met Ile Arg Glu Ala Asp Ile Asp Gly As - #p Gly Gln Val Asn Tyr           370              - #   375              - #   380                           - - Glu Glu Phe Val Gln Met Met Thr Ala Lys Gl - #y Gly Lys Arg Arg Trp       385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - Lys Lys Asn Phe Ile Ala Val Ser Ala Ala As - #n Arg Phe Lys Lys         Ile                                                                                              405  - #               410  - #               415              - - Ser Glu Leu Met Val Ser Lys Gly Glu Glu Le - #u Phe Thr Gly Val Val                   420      - #           425      - #           430                   - - Pro Ile Leu Val Glu Leu Asp Gly Asp Val As - #n Gly His Lys Phe Ser               435          - #       440          - #       445                       - - Val Ser Gly Glu Gly Glu Gly Asp Ala Thr Ty - #r Gly Lys Leu Thr Leu           450              - #   455              - #   460                           - - Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Va - #l Pro Trp Pro Thr Leu       465                 4 - #70                 4 - #75                 4 -       #80                                                                               - - Val Thr Thr Leu Thr Tyr Gly Val Gln Cys Ph - #e Ser Arg Tyr Pro         Asp                                                                                              485  - #               490  - #               495              - - His Met Lys Gln His Asp Phe Phe Lys Ser Al - #a Met Pro Glu Gly Tyr                   500      - #           505      - #           510                   - - Val Gln Glu Arg Thr Ile Phe Phe Lys Asp As - #p Gly Asn Tyr Lys Thr               515          - #       520          - #       525                       - - Arg Ala Glu Val Lys Phe Glu Gly Asp Thr Le - #u Val Asn Arg Ile Glu           530              - #   535              - #   540                           - - Leu Lys Gly Ile Asp Phe Lys Glu Asp Gly As - #n Ile Leu Gly His Lys       545                 5 - #50                 5 - #55                 5 -       #60                                                                               - - Leu Glu Tyr Asn Tyr Asn Ser His Asn Val Ty - #r Ile Met Ala Asp         Lys                                                                                              565  - #               570  - #               575              - - Gln Lys Asn Gly Ile Lys Val Asn Phe Lys Il - #e Arg His Asn Ile Glu                   580      - #           585      - #           590                   - - Asp Gly Ser Val Gln Leu Ala Asp His Tyr Gl - #n Gln Asn Thr Pro Ile               595          - #       600          - #       605                       - - Gly Asp Gly Pro Val Leu Leu Pro Asp Asn Hi - #s Tyr Leu Ser Thr Gln           610              - #   615              - #   620                           - - Ser Ala Leu Ser Lys Asp Pro Asn Glu Lys Ar - #g Asp His Met Val Leu       625                 6 - #30                 6 - #35                 6 -       #40                                                                               - - Leu Glu Phe Val Thr Ala Ala Gly Ile Thr Le - #u Gly Lys Asp Glu         Leu                                                                                              645  - #               650  - #               655              - -  - - (2) INFORMATION FOR SEQ ID NO:9:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 26 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:                                - - Lys Arg Arg Trp Lys Lys Asn Phe Ile Ala Va - #l Ser Ala Ala Asn Arg         1               5 - #                 10 - #                 15               - - Phe Lys Lys Ile Ser Ser Ser Gly Ala Leu                                                20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:10:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:                               - - Ala Arg Arg Lys Trp Gln Lys Thr Gly His Al - #a Val Arg Ala Ile Gly         1               5 - #                 10 - #                 15               - - Arg Leu Ser Ser                                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:11:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:                               - - Ala Arg Arg Lys Leu Lys Gly Ala Ile Leu Th - #r Thr Met Leu Ala Thr         1               5 - #                 10 - #                 15               - - Arg Asn Phe Ser                                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:12:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 17 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:                               - - Gly Val Arg Asn Ile Lys Ser Met Trp Glu Ly - #s Gly Asn Val Phe Ser         1               5 - #                 10 - #                 15               - - Ser                                                                        - -  - - (2) INFORMATION FOR SEQ ID NO:13:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:                               - - Ala Arg Arg Lys Leu Lys Ala Ala Val Lys Al - #a Val Val Ala Ser Ser         1               5 - #                 10 - #                 15               - - Arg Leu Gly Ser                                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:14:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 26 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:                               - - Phe Met Asn Asn Trp Glu Val Tyr Lys Leu Le - #u Ala His Ile Arg Pro         1               5 - #                 10 - #                 15               - - Pro Ala Pro Lys Ser Gly Ser Tyr Thr Val                                                20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:15:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 24 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:                               - - Ala Arg Lys Glu Val Ile Arg Asn Lys Ile Ar - #g Ala Ile Gly Lys Met         1               5 - #                 10 - #                 15               - - Ala Arg Val Phe Ser Val Leu Arg                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:16:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 26 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:                               - - Leu Arg Arg Leu Ile Asp Ala Tyr Ala Phe Ar - #g Ile Tyr Gly His Trp         1               5 - #                 10 - #                 15               - - Val Lys Lys Gly Gln Gln Gln Asn Arg Gly                                                20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:17:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 27 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:                               - - Arg Gly Lys Phe Lys Val Ile Cys Leu Thr Va - #l Leu Ala Ser Val Arg         1               5 - #                 10 - #                 15               - - Ile Tyr Tyr Gln Tyr Arg Arg Val Lys Pro Gl - #y                                        20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:18:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 28 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:                               - - Leu Arg Arg Gly Gln Ile Leu Trp Phe Arg Gl - #y Leu Asn Arg Ile Gln         1               5 - #                 10 - #                 15               - - Thr Gln Ile Lys Val Val Asn Ala Phe Ser Se - #r Ser                                    20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:19:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 21 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:                               - - Arg Arg Lys His Leu Gln Arg Pro Ile Phe Ar - #g Leu Arg Cys Leu Val         1               5 - #                 10 - #                 15               - - Lys Gln Leu Glu Lys                                                                    20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:20:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 21 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20:                               - - Thr Glu Lys Met Trp Gln Arg Leu Lys Gly Il - #e Leu Arg Cys Leu Val         1               5 - #                 10 - #                 15               - - Lys Gln Leu Glu Lys                                                                    20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:21:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 23 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21:                               - - Lys Arg Arg Ala Ile Gly Phe Lys Lys Leu Al - #a Glu Ala Val Lys Phe         1               5 - #                 10 - #                 15               - - Ser Ala Lys Leu Met Gly Gln                                                            20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:22:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 28 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22:                               - - Ile Lys Pro Ala Lys Arg Met Lys Phe Lys Th - #r Val Cys Tyr Leu Leu         1               5 - #                 10 - #                 15               - - Val Gln Leu Met His Cys Arg Lys Met Phe Ly - #s Ala                                    20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:23:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23:                               - - Ile Asp Leu Leu Trp Lys Ile Ala Arg Ala Gl - #y Ala Arg Ser Ala Val         1               5 - #                 10 - #                 15               - - Gly Thr Glu Ala                                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:24:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 27 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:24:                               - - Lys Ala His Lys Ala Ala Thr Lys Ile Gln Al - #a Ser Phe Arg Gly His         1               5 - #                 10 - #                 15               - - Ile Thr Arg Lys Lys Leu Lys Gly Glu Lys Ly - #s                                        20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:25:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 24 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25:                               - - Lys Thr Ala Ser Pro Trp Lys Ser Ala Arg Le - #u Met Val His Thr Val         1               5 - #                 10 - #                 15               - - Ala Thr Phe Asn Ser Ile Lys Glu                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:26:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 25 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:26:                               - - Lys Lys Lys Lys Lys Arg Phe Ser Phe Lys Ly - #s Ser Phe Lys Leu Ser         1               5 - #                 10 - #                 15               - - Gly Phe Ser Phe Lys Lys Ser Lys Lys                                                    20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:27:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 24 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:27:                               - - Lys Lys Lys Lys Lys Phe Ser Phe Lys Lys Pr - #o Phe Lys Leu Ser Gly         1               5 - #                 10 - #                 15               - - Leu Ser Phe Lys Arg Asn Arg Lys                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:28:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 31 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:28:                               - - Lys Gln Gln Lys Glu Lys Thr Arg Trp Leu As - #n Thr Pro Asn Thr Tyr         1               5 - #                 10 - #                 15               - - Leu Arg Val Asn Val Ala Asp Glu Val Gln Ar - #g Asn Met Gly Ser                        20     - #             25     - #             30                   - -  - - (2) INFORMATION FOR SEQ ID NO:29:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 21 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:29:                               - - Lys Asp Gln Val Ala Asn Ser Ala Phe Gln Gl - #u Arg Leu Arg Lys His         1               5 - #                 10 - #                 15               - - Gly Leu Glu Val Ile                                                                    20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:30:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 21 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:30:                               - - Tyr His Arg Leu Arg Asp Leu Leu Leu Ile Va - #l Lys Arg Ile Val Glu         1               5 - #                 10 - #                 15               - - Leu Leu Gly Arg Arg                                                                    20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:31:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 23 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:31:                               - - Gln Gln Leu Ala Thr Leu Ile Gln Lys Thr Ty - #r Arg Gly Trp Arg Cys         1               5 - #                 10 - #                 15               - - Arg Thr His Tyr Gln Leu Met                                                            20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:32:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 24 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:32:                               - - Arg Ala Ala Cys Ile Arg Ile Gln Lys Thr Il - #e Arg Gly Trp Leu Leu         1               5 - #                 10 - #                 15               - - Arg Lys Arg Tyr Leu Cys Met Gln                                                        20                                                                 - -  - - (2) INFORMATION FOR SEQ ID NO:33:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 14 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:33:                               - - Ile Asn Leu Lys Ala Leu Ala Ala Leu Ala Ly - #s Lys Ile Leu                 1               5 - #                 10                                      - -  - - 2) INFORMATION FOR SEQ ID NO:34:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 26 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:34:                               - - Gly Ile Gly Ala Val Leu Lys Val Leu Thr Th - #r Gly Leu Pro Ala Leu         1               5 - #                 10 - #                 15               - - Ile Ser Trp Ile Lys Arg Lys Arg Gln Gln                                                20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:35:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 30 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:35:                               - - His Ser Gln Gly Thr Phe Thr Thr Ser Asp Ty - #r Ser Lys Tyr Leu Asp         1               5 - #                 10 - #                 15               - - Ser Arg Arg Ala Gln Asp Phe Val Gln Trp Le - #u Met Asn Thr                            20     - #             25     - #             30                   - -  - - (2) INFORMATION FOR SEQ ID NO:36:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 27 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:36:                               - - His Ser Asp Gly Thr Phe Thr Ser Glu Leu Se - #r Arg Leu Arg Asp Ser         1               5 - #                 10 - #                 15               - - Ala Arg Leu Gln Arg Leu Leu Gln Gly Leu Va - #l                                        20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:37:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 28 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:37:                               - - His Ser Asp Ala Val Phe Thr Asp Asn Tyr Th - #r Arg Leu Arg Lys Gln         1               5 - #                 10 - #                 15               - - Met Ala Val Lys Lys Tyr Leu Asn Ser Ile Le - #u Asn                                    20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:38:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 33 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:38:                               - - Tyr Ala Asp Gly Thr Phe Ile Ser Asp Tyr Se - #r Ala Ile Met Asn Lys         1               5 - #                 10 - #                 15               - - Ile Arg Gln Gln Asp Phe Val Asn Trp Leu Le - #u Ala Gln Gln Gln Lys                    20     - #             25     - #             30                   - - Ser                                                                        - -  - - (2) INFORMATION FOR SEQ ID NO:39:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 17 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:39:                               - - Lys Leu Trp Lys Lys Leu Leu Lys Leu Leu Ly - #s Lys Leu Leu Lys Leu         1               5 - #                 10 - #                 15               - - Gly                                                                        - -  - - (2) INFORMATION FOR SEQ ID NO:40:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (D) OTHER INFORMATION: - #linker moiety; sequence repeated                          indefinitely                                                     - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:40:                               - - Gly Gly Gly Gly Ser                                                         1               5                                                             - -  - - (2) INFORMATION FOR SEQ ID NO:41:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 12 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:41:                               - - Gly Lys Ser Ser Gly Ser Gly Ser Glu Ser Ly - #s Ser                         1               5 - #                 10                                      - -  - - (2) INFORMATION FOR SEQ ID NO:42:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 14 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:42:                               - - Gly Ser Thr Ser Gly Ser Gly Lys Ser Ser Gl - #u Gly Lys Gly                 1               5 - #                 10                                      - -  - - (2) INFORMATION FOR SEQ ID NO:43:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 18 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:43:                               - - Gly Ser Thr Ser Gly Ser Gly Lys Ser Ser Gl - #u Gly Ser Gly Ser Thr         1               5 - #                 10 - #                 15               - - Lys Gly                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:44:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 14 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:44:                               - - Gly Ser Thr Ser Gly Ser Gly Lys Ser Ser Gl - #u Gly Lys Gly                 1               5 - #                 10                                      - -  - - 2) INFORMATION FOR SEQ ID NO:45:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 18 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:45:                               - - Gly Ser Thr Ser Gly Ser Gly Lys Pro Gly Se - #r Gly Glu Gly Ser Thr         1               5 - #                 10 - #                 15               - - Lys Gly                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:46:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 14 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:46:                               - - Glu Gly Lys Ser Ser Gly Ser Gly Ser Glu Se - #r Lys Glu Phe                 1               5 - #                 10                                      - -  - - 2) INFORMATION FOR SEQ ID NO:47:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:47:                               - - Lys Lys Lys Arg Lys                                                         1               5                                                             - -  - - 2) INFORMATION FOR SEQ ID NO:48:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 26 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:48:                               - - Met Leu Arg Thr Ser Ser Leu Phe Thr Arg Ar - #g Val Gln Pro Ser Leu         1               5 - #                 10 - #                 15               - - Phe Arg Asn Ile Leu Arg Leu Gln Ser Thr                                                20     - #             25                                          - -  - - (2) INFORMATION FOR SEQ ID NO:49:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:49:                               - - Lys Asp Glu Leu                                                             1                                                                             - -  - - 2) INFORMATION FOR SEQ ID NO:50:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 3 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:50:                               - - Ser Lys Phe                                                                 1                                                                             - -  - - 2) INFORMATION FOR SEQ ID NO:51:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:51:                               - - Cys Ala Ala Xaa                                                             1                                                                             - -  - - 2) INFORMATION FOR SEQ ID NO:52:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 2 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:52:                               - - Cys Cys                                                                     1                                                                             - -  - - 2) INFORMATION FOR SEQ ID NO:53:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 3 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:53:                               - - Cys Xaa Cys                                                                 1                                                                             - -  - - 2) INFORMATION FOR SEQ ID NO:54:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:54:                               - - Cys Cys Xaa Xaa                                                             1                                                                             - -  - - 2) INFORMATION FOR SEQ ID NO:55:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 10 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:55:                               - - Pro Lys Lys Lys Arg Lys Val Glu Asp Pro                                     1               5 - #                 10                                      - -  - - 2) INFORMATION FOR SEQ ID NO:56:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 18 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:56:                               - - Met Leu Leu Pro Val Pro Leu Leu Leu Gly Le - #u Leu Gly Leu Ala Ala         1               5 - #                 10 - #                 15               - - Ala Asp                                                                    - -  - - (2) INFORMATION FOR SEQ ID NO:57:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 15 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA                                                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Coding Se - #quence                                              (B) LOCATION: 1...15                                                  - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:57:                               - - GCT GCT CGC ATG CAT           - #                  - #                       - #    15                                                                   Ala Ala Arg Met His                                                              1               5                                                             - -  - - (2) INFORMATION FOR SEQ ID NO:58:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:58:                               - - la Ala Arg Met His                                                         1               5                                                              - -  - - 2) INFORMATION FOR SEQ ID NO:59:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 18 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA                                                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Coding Se - #quence                                              (B) LOCATION: 1...18                                                  - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:59:                               - - ATC TCC GAG CTC ATG AGT         - #                  - #                       - #  18                                                                   Ile Ser Glu Leu Met Ser                                                          1               5                                                             - -  - - (2) INFORMATION FOR SEQ ID NO:60:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:60:                               - - Ile Ser Glu Leu Met Ser                                                     1               5                                                             - -  - - (2) INFORMATION FOR SEQ ID NO:61:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 18 amino - #acids                                                  (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:61:                               - - Met Leu Leu Ser Val Pro Leu Leu Leu Gly Le - #u Leu Gly Leu Ala             1               5 - #                 10 - #                 15               - - Ala Ala Asp                                                              __________________________________________________________________________ 

What is claim is:
 1. An isolated nucleic acid sequence which encodes a fluorescent indicator, the indicator comprising:a binding protein moiety having an analyte-binding region which binds an analyte and causes the indicator to change conformation upon exposure to the analyte; a donor fluorescent protein moiety covalently coupled to the binding protein moiety; and an acceptor fluorescent protein moiety covalently coupled to the binding protein moiety, wherein the donor moiety and the acceptor moiety change position relative to each other when the analyte binds to the analyte-binding region, altering fluorescence resonance energy transfer between the donor moiety and the acceptor moiety when the donor moiety is excited.
 2. The nucleic acid of claim 1, wherein the donor fluorescent protein moiety and the acceptor fluorescent protein moiety are Aequorea-related fluorescent protein moieties.
 3. The nucleic acid of claim 2, wherein the indicator further includes a target peptide moiety and a linker moiety that covalently couples the binding protein and the target peptide moiety and is a peptide moiety, and the binding protein moiety further includes a peptide-binding region for binding the target peptide moiety.
 4. The nucleic acid of claim 3, wherein the donor fluorescent protein moiety is fused to the binding protein moiety and the acceptor fluorescent protein moiety is fused to the target peptide moiety.
 5. The nucleic acid of claim 2, wherein the binding protein moiety is calmodulin, a calmodulin-related protein moiety, cGMP-dependent protein kinase, a steroid hormone receptor, a ligand binding domain of a steroid hormone receptor, protein kinase C, inositol-1,4,5-triphosphate receptor, or recoverin.
 6. The nucleic acid of claim 3, wherein the binding protein moiety is calmodulin or a calmodulin-related protein moiety.
 7. The nucleic acid of claim 6, wherein the donor fluorescent protein moiety is P4-3, EBFP, or W1B, and the acceptor fluorescent protein moiety is S65T, EGFP, or 10c.
 8. The nucleic acid of claim 6, wherein the target peptide moiety is a calmodulin-binding domain of skMLCKp, smMLCK, CaMKII, Caldesmon, Calspermin, phosphofructokinase calcineurin, phosphorylase kinase, Ca2+-ATPase 59 kDa PDE, 60 kDa PDE, nitric oxide synthase, type I adenylyl cylclase, Bordetella pertussis adenylyl cyclase, Neuromodulin, S-pectrin, MARCKS, F52, β-Adducin, HSP90a, HIV-1 gp160, BBMHBI, Dilute MHC, Mastoparan, Melittin, Glucagon, Secretin, VIP, GIP, or Model Peptide CBP2.
 9. The nucleic acid of claim 6, wherein the target peptide moiety is M13.
 10. The nucleic acid of claim 9, wherein the linker moiety is --Gly-Gly--.
 11. The nucleic acid of claim 1, wherein the indicator further comprises a localization sequence.
 12. An expression vector comprising the nucleic acid sequence of claim
 1. 13. An expression vector comprising expression control sequences operatively linked to a nucleic acid sequence coding for the expression of a fluorescent indicator, the indicator comprising:a binding protein moiety having an analyte-binding region which binds an analyte and causes the indicator to change conformation upon exposure to the analyte; a donor fluorescent protein moiety fused to the binding protein moiety; and an acceptor fluorescent protein moiety fused to the binding protein moiety, wherein the donor moiety and the acceptor moiety change position relative to each other when the analyte binds to the analyte-binding region, altering fluorescence resonance energy transfer between the donor moiety and the acceptor moiety when the donor moiety is excited.
 14. The expression vector of claim 13 adapted for function in a prokaryotic cell.
 15. The expression vector of claim 13 adapted for function in a eukaryotic cell.
 16. A host cell transfected with an expression vector comprising an expression control sequence operatively linked to a sequence coding for the expression of a fluorescent indicator, the indicator comprising:a binding protein moiety having an analyte-binding region which binds an analyte and causes the indicator to change conformation upon exposure to the analyte; a donor fluorescent protein moiety covalently coupled to the binding protein moiety; and an acceptor fluorescent protein moiety covalently coupled to the binding protein moiety, wherein the donor moiety and the acceptor moiety change position relative to each other when the analyte binds to the analyte-binding region, altering fluorescence resonance energy transfer between the donor moiety and the acceptor moiety when the donor moiety is excited.
 17. The cell of claim 16, wherein the cell is a prokaryote.
 18. The cell of claim 17, wherein the cell is E. coli.
 19. The cell of claim 16, wherein the cell is a eukaryotic cell.
 20. The cell of claim 19, wherein the cell is a yeast cell.
 21. The cell of claim 19, wherein the cell is a mammalian cell. 